This page gives you the complete masculine definite paradigm — all eight cells — and shows you the mechanics behind each one. The principle is established on the overview page: you decline the noun first, then suffix the article, which itself declines to match. Here we apply that to a strong masculine, hestur ("horse", kk), and watch every cell. The masculine is where the fusions are most visible: the article "eats" part of the ending in the nominative singular, the genitive stacks the noun's -s with the article's -ins, and the dative plural piles two -um-like elements on top of each other. Once you can build hesturinn → hestinn → hestinum → hestsins and the plural, you own the masculine.
The full paradigm: hestur
Here is hestur with the definite article, all four cases in both numbers. The bare (indefinite) form is given alongside so you can see exactly what the article adds:
| Case | Singular (indef.) | Singular (def.) | Plural (indef.) | Plural (def.) |
|---|---|---|---|---|
| Nefnifall (nom.) | hestur | hesturinn | hestar | hestarnir |
| Þolfall (acc.) | hest | hestinn | hesta | hestana |
| Þágufall (dat.) | hesti | hestinum | hestum | hestunum |
| Eignarfall (gen.) | hests | hestsins | hesta | hestanna |
The article's own forms, isolated, are: singular -inn / -inn / -num / -ins, plural -nir / -na / -num / -nna. But you rarely add them cleanly — they fuse with the noun's ending, and the fusions are the whole lesson.
The nominative singular: the article eats the ending
The first surprise is in the nominative singular. The indefinite is hestur; the article is -inn. You might expect hestur + inn = hesturinn, and indeed the surface result is hesturinn — but understand what happened. The article descends from the old demonstrative hinn, and its h- has dropped, leaving -inn, which simply attaches after the full nominative hestur. The two don't collide here, so you keep both: hestur + inn → hesturinn (not hesturhinn, and not hestinn).
Hesturinn er þreyttur eftir daginn.
The horse is tired after the day. Nominative singular 'hesturinn' = 'hestur' (full nom.) + '-inn'.
Contrast the accusative singular, where the noun's bare form is hest (no -ur), so the article attaches to that: hest + inn → hestinn. This is why the nominative keeps -ur- but the accusative does not.
Ég sá hestinn úti á túni.
I saw the horse out in the field. Accusative singular 'hestinn' = 'hest' (acc.) + '-inn' — no -ur-, because the accusative noun is just 'hest'.
The dative singular and the genitive -sins
The dative singular noun is hesti; the article's dative is -num: hesti + num → hestinum. Both halves are dative — hesti says dative, -num says dative again (the double case-marking discussed on the overview page).
Hnakkurinn hvílir á hestinum.
The saddle rests on the horse. Dative singular 'hestinum' = 'hesti' (dat.) + '-num'; 'á' takes the dative.
The genitive singular is the one to spell carefully. The noun's genitive is hests (with -s); the article's genitive is -ins; together: hests + ins → hestsins. You end up with the -s of the noun followed by -ins of the article — hests-ins. Don't drop the noun's -s.
Eigandi hestsins býr í næsta húsi.
The owner of the horse lives in the next house. Genitive singular 'hestsins' = 'hests' (gen.) + '-ins' — keep both -s and -ins.
Verð hestsins kom mér á óvart.
The price of the horse surprised me. 'hestsins' again — the genitive is the form behind English 'of the horse' / 'the horse's'.
The plural: hestarnir, hestana, hestunum, hestanna
The plural is regular once you see the joins. Nominative noun hestar + article -nir → hestarnir. Accusative noun hesta + -na → hestana. Genitive noun hesta + -nna → hestanna.
Hestarnir á bænum eru íslenskir.
The horses on the farm are Icelandic. Nominative plural 'hestarnir' = 'hestar' + '-nir'.
Bóndinn rekur hestana inn í hesthúsið.
The farmer drives the horses into the stable. Accusative plural 'hestana' = 'hesta' + '-na'.
Litur hestanna er mismunandi.
The colour of the horses varies. Genitive plural 'hestanna' = 'hesta' + '-nna' — double n in the article's genitive plural.
The dative plural is the cell everyone fumbles: hestunum. The noun's dative plural already ends in -um (hestum), and the article's dative is also -um, so the form stacks two -um-like elements: hest-u-num. Build it as hestum + um → hestunum (the noun's -um and the article's -num merge into -unum). The result has the distinctive -unum that signals "dative plural definite."
Heyið er gefið hestunum á morgnana.
The hay is given to the horses in the mornings. Dative plural 'hestunum' = 'hestum' + the dative article, fusing to '-unum'.
The weak -i masculine: tími
Weak masculines end in -i (gen. = acc. = dat. = stem in -a). They take the same article but join differently because the noun ends in a vowel. Model: tími ("time, hour"):
| Case | Singular (indef.) | Singular (def.) |
|---|---|---|
| Nefnifall (nom.) | tími | tíminn |
| Þolfall (acc.) | tíma | tímann |
| Þágufall (dat.) | tíma | tímanum |
| Eignarfall (gen.) | tíma | tímans |
Note tími + nn → tíminn (the final -i absorbs the article's i, giving a single -i- plus double n) and the accusative tíma + nn → tímann. The genitive is the clean tímans (no extra -s, because the weak noun's genitive is just tíma, not tímas) — contrast the strong hestsins.
Tíminn líður hratt þegar maður skemmtir sér.
Time flies when you're having fun. Nominative 'tíminn' = 'tími' + the article (i + nn → -inn).
Ég hef ekki tímann í dag.
I don't have the time today. Accusative 'tímann' = 'tíma' + '-nn' — double n.
Eftir hálftíma kemur strætó. Ég bíð eftir tímanum.
The bus comes in half an hour. I'm waiting for the moment. Dative 'tímanum' = 'tíma' + the dative article '-num'.
Common Mistakes
❌ Confusing nom. and acc.: 'Ég sá hesturinn'
Incorrect — the object is accusative; the accusative definite is 'hestinn', not 'hesturinn'.
✅ Ég sá hestinn.
I saw the horse. Accusative 'hestinn' (the noun underneath is 'hest', not 'hestur').
❌ Single n in the nominative suffix: 'hesturin'
Incorrect — the masculine nom.sg article is '-inn' with a double n.
✅ hesturinn
the horse — double n.
❌ Dropping the noun's -s in the genitive: 'hestins'
Incorrect — the strong masculine genitive keeps its -s, then adds the article '-ins': 'hestsins'.
✅ hestsins
of the horse / the horse's — 'hests' + '-ins'.
❌ Single -um in the dative plural: 'hestum' for 'to the horses' (definite)
Incorrect — the definite dative plural stacks the noun's -um and the article's -um, giving '-unum': 'hestunum'.
✅ hestunum
to the horses — dative plural definite, '-unum'.
❌ Adding an extra -s to a weak genitive: 'tímasins'
Incorrect — the weak noun's genitive is just 'tíma', so the definite is 'tímans', with no doubled -s.
✅ tímans
of the time — 'tíma' + '-ns'.
Key Takeaways
- Singular: hesturinn, hestinn, hestinum, hestsins. Plural: hestarnir, hestana, hestunum, hestanna.
- The nominative keeps the noun's -ur (hestur
- -inn → hesturinn); the accusative drops it (hest
- -inn → hestinn). Decline the noun first.
- -inn → hesturinn); the accusative drops it (hest
- The strong genitive stacks -s + -ins → hestsins; the weak genitive has no -s → tímans.
- The masculine nom.sg article is -inn with a double n.
- The definite dative plural is -unum in every gender, fusing the noun's -um with the article's -um (hestunum).
- A weak -i masculine (tími) joins the same article through its vowel: tíminn, tímann, tímanum, tímans.
Now practice Icelandic
Reading grammar gets you part of the way. The exercises are where it sticks — free, no signup needed.
Start learning Icelandic→Related Topics
- The Suffixed Definite ArticleA1 — Icelandic has no separate word for 'the' and no word for 'a' — definiteness is a declined article suffixed onto the already-declined noun, so a definite noun marks its case twice (hestur → hesturinn, borð → borðið, hesti → hestinum).
- Strong Masculine Nouns: OverviewA2 — The strong masculine declensions — the largest noun group, marked by a genitive singular in -s and a nominative plural in -ar or -ir — with the all-important insight that the -ur of the nominative is an ending, not part of the stem.
- Definite Article: Feminine ParadigmA2 — The full suffixed definite article on feminine nouns — strong borgin, borgina, borginni, borgarinnar and weak konan, konuna, konunni, konunnar — with the doubled -nn- of the dative and genitive singular that is the gender's signature spelling trap.