slíkur, þvílíkur, svona: 'such' and 'this kind'

English has two overlapping ways to say "such" — the neutral such a book and the exclamative what a book! — and it also has loose phrases like this kind of and things like this. Icelandic carves this territory up with three distinct words, and the trap for learners is that dictionaries list all three as "such" and let you assume they are interchangeable. They are not. slíkur is the neutral, fully declining "such" (slík bók "such a book") — the workhorse of careful prose. þvílíkur is not really a synonym of slíkur at all: it is overwhelmingly exclamative, the Icelandic "what (a)…!" (Þvílíkur dagur! "what a day!"), carrying emotional force a plain "such" does not. And svona, þannig, svoleiðis are invariant — they never change shape — and belong to colloquial speech: "like this / like that / this kind of" (svona hlutir "things like this"). Sorting these three out — which declines, which is exclamative, which never moves — is the whole job of this page. (Basic þessi / sá demonstratives are on their own page; here we handle the "such / this kind" layer that sits on top.)

slíkur: the neutral, declining 'such'

slíkur / slík / slíkt is the everyday, register-neutral "such" — "a thing of that kind". It is a normal adjective-type word and declines fully for gender, number and case, agreeing with its noun: slíkur maður "such a man", slík bók "such a book", slíkt mál "such a matter", slíkir hlutir "such things". It is the word you want in writing and in any careful statement; it reports "of that kind" without emotional colour.

Note one thing English speakers expect and don't get: there is no "a" to worry about. English "such a book" needs the article; Icelandic slík bók is bare — slíkur itself carries the "such a" meaning, and you simply decline it onto the noun. A very common standalone use is the neuter slíkt "such a thing / anything like that": Ég hef aldrei séð slíkt "I have never seen such a thing".

þvílíkur: the exclamative 'what a…!'

Here is the distinction competitors miss. þvílíkur is not a stylistic variant of slíkur — its core function is exclamative. It is the Icelandic "what (a)…!", the word you fling out in admiration, dismay, or astonishment: Þvílíkur dagur! "what a day!", Þvílík heppni! "what luck!", Þvílík vitleysa! "what nonsense!". It declines like slíkur (þvílíkur / þvílík / þvílíkt) and agrees with its noun, but it lives in exclamations, typically clause-initial and standing alone or heading an exclamative phrase. Using slíkur where the situation calls for þvílíkur drains the sentence of its emotion; using þvílíkur in a flat descriptive sentence sounds oddly histrionic.

svona, þannig, svoleiðis: the invariant colloquials

The third group is the colloquial one, and its defining property is that these words never decline. svona "like this", þannig "like that / in that way", and svoleiðis "that kind / like that" are invariant — one fixed shape regardless of the gender, number, or case of the noun they sit beside. svona hlutir "things like this", svona bíll "a car like this", svona fólk "people like that" — svona itself does not change. This is exactly the opposite of slíkur and þvílíkur, and the most common error here is trying to inflect them by analogy with the declining "such" words.

Choosing between them

Three quick questions settle almost every case. Are you exclaiming — "What a…!" with feeling? Use þvílíkur, agreed in gender (Þvílíkur dagur!). Are you writing carefully or speaking formally, reporting "of that kind" with no emotion? Use the declining slíkur (slík bók, í slíkum tilfellum). Are you speaking casually, "a thing like this / that sort of"? Use the invariant svona / þannig / svoleiðis (svona hlutir). In practice slíkur and svona often cover the same ground — slík bók and svona bók both mean roughly "a book like this" — but slíkur lifts the register and svona lowers it, while þvílíkur moves you out of description and into exclamation entirely.

Why English sets the trap

English blurs all of this. The single word such covers both the neutral "such a book" and, with rising intonation, an exclamative flavour; and English freely uses loose phrases ("this kind of", "like that") with no inflection at all. So an English speaker arrives with one undifferentiated concept and no instinct that (a) the neutral "such" must agree like an adjective (slík, slíkan, slíkum), (b) the exclamative "what a…!" is a separate word (þvílíkur) with its own emotional job, and (c) the casual "like this" words never inflect (svona). The corrections are three: agree slíkur; keep þvílíkur for exclamations; and leave svona / þannig / svoleiðis completely alone.

Common Mistakes

Key Takeaways

• slíkur / slík / slíkt is the neutral, fully declining "such (of that kind)" — agree it with the noun (slík bók, slíkum tilfellum); no "a" needed. Standalone neuter slíkt = "such a thing".
• þvílíkur is primarily the exclamative "what (a)…!" (Þvílíkur dagur!, Þvílík heppni!, Þvílíkt rugl!) — it declines and agrees, but lives in exclamations and carries emotion; it is not a flat synonym of slíkur.
• svona / þannig / svoleiðis are invariant, colloquial "like this / like that / this kind of" (svona hlutir, þannig fólk) — they never decline.
• Choose by intent: exclaiming → þvílíkur; careful/formal description → slíkur; casual speech → svona/þannig/svoleiðis.
• English's single, uninflected such sets the trap: agree slíkur, reserve þvílíkur for exclamations, and leave svona uninflected.