Colours are the perfect place to drill adjective agreement, and not by accident: the everyday colour set is small, frequent, and unusually rich in irregular neuters. In nine words you meet the strong neuter -t, its assimilation after awkward stems, the doubling -tt that vowel-stem colours produce, and the feminine u-umlaut that turns svartur into svört. This page is not a vocabulary list — for the words themselves, when to use dökk- and ljós-, and how to describe things, see colours and description. Here we do one thing: make the colours agree correctly in gender, number, definiteness, and case. If you can decline the colours, you can decline almost any adjective.
The core colours in all three genders
Every adjective in Icelandic agrees with its noun, and colours are no exception: there is no single fixed word for "red" — there is rauður (with a masculine noun), rauð (feminine), and rautt (neuter). Here is the strong nominative singular trio for the nine core colours — the form you use when there's no article (rauður bíll, "a red car") and the form a predicate takes (bíllinn er rauður, "the car is red"):
| Colour | Masculine | Feminine | Neuter |
|---|---|---|---|
| red | rauður | rauð | rautt |
| blue | blár | blá | blátt |
| green | grænn | græn | grænt |
| yellow | gulur | gul | gult |
| white | hvítur | hvít | hvítt |
| black | svartur | svört | svart |
| brown | brúnn | brún | brúnt |
| grey | grár | grá | grátt |
| pink | bleikur | bleik | bleikt |
Read the columns and a pattern emerges. The masculine is the dictionary form (in -ur, or just -r/-nn after a long vowel or n). The feminine is the bare stem — strip the masculine ending and you usually have it: rauð, blá, græn. The neuter adds -t, and that one ending hides all the action on this page.
Ég keypti rauðan jakka og bláa húfu.
I bought a red jacket and a blue hat. (jakki is masculine → rauðan acc.; húfa is feminine → bláa acc.)
Hún á svartan kött og hvítan hund.
She has a black cat and a white dog. (köttur masc. → svartan; hundur masc. → hvítan, both accusative)
The neuter -t: three things that can happen
The neuter ending is -t, but how it attaches depends on what the stem ends in. There are three outcomes, and colours show all three:
- Clean -t — after most consonants the -t just lands: gulur → gult, grænn → grænt, brúnn → brúnt, bleikur → bleikt.
- Doubling to -tt — when the stem ends in a long vowel, Icelandic writes the neuter as -tt: blár → blátt, grár → grátt, and (vowel + t fusing) hvítur → hvítt, rauður → rautt. This is the cell English speakers get wrong most often.
- Assimilation to a single -t — when the stem already ends in -t, you don't double it: svartur (stem svart-) → neuter svart, not *"svartt".
So the neuters that look "irregular" are really just the regular -t rule meeting different stems. The doubled blátt / grátt is the headline trap: learners reach for "blárt" by analogy with gult, but a long vowel forces -tt.
Húsið er hvítt og þakið er rautt.
The house is white and the roof is red. (hús and þak are both neuter → hvítt, rautt)
Hafið var alveg blátt í morgun.
The sea was completely blue this morning. (haf is neuter → blátt, the doubled vowel-stem neuter)
Þetta er fallegt, grátt teppi.
This is a beautiful grey blanket. (teppi is neuter → grátt; note the doubled -tt after the long vowel)
The feminine u-umlaut: svartur → svört
Most colours form their feminine by simply dropping the masculine ending: rauð, blá, gul. But one core colour hides the language's signature sound change. Svartur has the stem vowel a, and the feminine ending historically carried a -u, which triggers u-umlaut: the a rounds to ö. So "black" is svartur (m.) but svört (f.):
| Masculine | Feminine | Neuter | |
|---|---|---|---|
| nom. sg | svartur | svört | svart |
| nom./acc. pl (neut.) | — | — | svört |
| dat. pl (all genders) | svörtum | ||
This is the only core colour with the umlaut, because it is the only one with an a in the stem. Crucially, gulur does not umlaut: its stem vowel is u, not a, so the feminine is plainly gul — there is no a to round. Beginners over-apply the rule and produce "göl"; resist it. The umlaut converts a → ö only, and only when an -u (or a vanished historical -u) follows.
Hún var í svartri kápu og með svört gleraugu.
She was in a black coat and wearing black glasses. (kápa fem. dat. after í → svartri; gleraugu neut. pl → svört)
Kisan mín er svört með hvítar loppur.
My cat is black with white paws. (kisa is feminine → svört; loppur fem. pl acc. → hvítar)
Ég vil frekar gula peysu en svarta.
I'd rather have a yellow jumper than a black one. (peysa fem. acc. → gula / svarta; gul has no umlaut, svart does in other cells)
Attributive definite: the weak forms (rauði bíllinn)
Everything above is the strong declension. The moment the noun phrase becomes definite — with the suffixed article, a demonstrative, or a possessive — the colour switches to its weak form. The weak colours are gentle: masculine nominative ends in -i, almost everything else in -a (with -u in the feminine oblique and the plural). So "the red car" is rauði bíllinn, not "rauður bíllinn":
| Strong (indefinite) | Weak (definite) |
|---|---|
| rauður bíll — "a red car" | rauði bíllinn — "the red car" |
| blá peysa — "a blue jumper" | bláa peysan — "the blue jumper" |
| svart hús — "a black house" | svarta húsið — "the black house" |
Notice the double marking: the article is on the noun (bíllinn) and the adjective has gone weak (rauði). Both say "definite" at once — you don't drop one. The weak masculine forms of the colours are exactly what you'd predict: rauði, blái, græni, guli, hvíti, svarti, brúni, grái, bleiki. (For the full mechanism, see the weak declension.)
Rauði bíllinn þarna er minn.
The red car over there is mine. (definite phrase → weak rauði + article -inn)
Manstu eftir bláu peysunni sem ég var í?
Do you remember the blue jumper I was wearing? (definite, feminine dative → weak bláu + article)
Predicate vs attributive: a quick contrast
The single most useful habit is to feel the difference between a colour before a noun and a colour after vera. After vera the colour is a predicate and always strong, agreeing with the subject — even if the subject is definite:
Bíllinn er rauður, en hjólið er blátt.
The car is red, but the bike is blue. (predicates → strong: bíll masc. rauður, hjól neut. blátt)
Veggirnir eru gráir og gólfið er brúnt.
The walls are grey and the floor is brown. (veggir masc. pl → gráir; gólf neut. → brúnt)
Indeclinable colour words: appelsínugulur and the loan shades
The nine core colours all decline. But many finer shades are compounds or loans, and these behave in two different ways:
- Compounds ending in a real adjective still decline — only the last element changes. Appelsínugulur ("orange," literally "orange-yellow") is gulur with appelsínu- glued on the front, so it inflects exactly like gulur: appelsínugul (f.), appelsínugult (n.). The same goes for ljósblár ("light blue" → ljósblátt) and dökkgrænn ("dark green" → dökkgrænt).
- Bare loan colours are indeclinable — words like fjólublár decline (it ends in blár), but truly foreign, uninflected colour labels such as beis ("beige"), lilla ("lilac/purple"), turkís ("turquoise") and bordó ("burgundy") do not change at all. They sit frozen: lilla kjóll, lilla peysa, lilla hús — same form for every gender.
Hún keypti sér appelsínugula úlpu.
She bought herself an orange parka. (appelsínugulur declines like gulur → appelsínugula, fem. acc.)
Mér finnst lilla liturinn flottastur.
I think the lilac colour is the coolest. (lilla is indeclinable — frozen before any noun)
Common Mistakes
❌ Húsið er blárt.
Incorrect — a vowel-stem colour doubles to -tt, it does not insert -rt. There is no 'r' in the neuter.
✅ Húsið er blátt.
The house is blue. (neuter of blár = blátt)
❌ Hún er í svart úlpu.
Incorrect — the colour must agree: úlpa is feminine and dative after í, so svart → svartri. (And note the feminine of svartur umlauts.)
✅ Hún er í svartri úlpu.
She's in a black parka. (feminine dative svartri)
❌ Ég sá rauður bíll.
Incorrect — the object is accusative; the masculine strong colour becomes rauðan, not the nominative rauður (and the noun → bíl).
✅ Ég sá rauðan bíl.
I saw a red car. (accusative masculine rauðan)
❌ Rauður bíllinn er minn.
Incorrect — the phrase is definite (the article -inn), so the colour goes weak: rauði.
✅ Rauði bíllinn er minn.
The red car is mine. (definite → weak rauði)
❌ Hún á göla peysu.
Incorrect — gulur has stem vowel u, so it never umlauts; the feminine accusative is plainly gula.
✅ Hún á gula peysu.
She has a yellow jumper. (no umlaut — the stem has no a to round)
Key Takeaways
- Colours agree like any adjective: rauður / rauð / rautt. There is no fixed word for "red."
- The neuter -t does three things: lands cleanly (gult, grænt), doubles after a long vowel (blátt, grátt, hvítt, rautt), or fuses to a single -t after a t-stem (svart).
- Only svartur umlauts among the core colours: feminine svört (a → ö). Gulur keeps gul — its stem vowel is u, so there is nothing to round.
- A definite phrase makes the colour weak: rauði bíllinn, bláa peysan — and the noun still keeps its article (double marking).
- Compound colours decline on the last element (appelsínugult); bare loan colours (beis, lilla, turkís, bordó) are indeclinable.
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Start learning Icelandic→Related Topics
- The Strong (Indefinite) DeclensionA2 — The full strong adjective paradigm — used when the noun phrase is indefinite and for predicate adjectives — laid out for fallegur across all genders, cases, and numbers, with the neuter -t, the consonant-heavy feminine and genitive endings, and the u-umlaut that surfaces in a-stem adjectives like svangur → svöng.
- The Weak (Definite) DeclensionA2 — The full weak adjective paradigm — used after the definite article, demonstratives, and possessives — laid out for gamall, with its tiny inventory of -i and -a (and -u) endings, the rule that definiteness drives the choice, and the redundant double-marking (gamli maðurinn) that English speakers systematically under-produce.
- Describing People and ThingsA2 — Descriptive vocabulary in action — size, shape, appearance and character adjectives plus the agreement burden, attributive vs predicate use, and the description idiom 'vera með + accusative' for features (vera með blá augu, 'to have blue eyes').
- Icelandic Adjectives: Agreement and Two DeclensionsA2 — The big picture of the Icelandic adjective: it agrees with its noun in gender, number, and case, AND it has two complete declensions — strong (indefinite, gamall maður) and weak (definite, gamli maðurinn) — so a single adjective has dozens of forms, chosen by the definiteness of the whole noun phrase.