Adjective Declensions

Adjective endings are not completely regular in Icelandic. They depend on the ending of the base of the word to a degree. Other parts of the word may also change in some cases. A sound change may happen to vowels. This is what is called „hljóðvarp“ in Icelandic. It is the same concept as the Umlaut in German. Adjective declinations for case, gender and number are still regular enough that one should be able to get a fair understanding of their patterns with some practice.

Let's look at the adjective for new

Without an article

	Masculine	Feminine	Neuter
Vardinis	nýr	ný	nýtt
Akusatyvas	nýjan	nýja	nýtt
daiktavardis	nýjum	nýrri	nýju
Genityvas	nýs	nýrrar	nýs

	Plural masculine	Plural feminine	Plurar neuter
Nominatyvas	nýir	nýjar	ný
Akusatyvas	nýja	nýjar	ný
Datyvas	nýjum	nýjum	nýjum
Genetive	nýrra	nýrra	nýrra

With the definite article

	Vyriška	Moteriška	Neutrali	Daugiskaita
Vardinis	nýi	nýja	nýja	nýju
Akusatyvas	nýja	nýju	nýja	nýju
daiktavardis	nýja	nýju	nýja	nýju
Genityvas	nýja	nýju	nýja	nýju

Here is another example of an adjective, fast, which does in some cases have „hljóðvarp“ (vowel changes)

	Vyriška	Moteriška	Neutrali
Vardinis	hraður	hröð	hratt
Akusatyvas	hraðan	hraða	hratt
daiktavardis	hröðum	hraðri	hröðu
Genityvas	hraðs	hraðrar	hraðs

	Plural masculine	Plural feminine	Plurar neuter
Nominatyvas	hraðir	hraðar	hröð
Akusatyvas	hraða	hraðar	hröð
Datyvas	hröðum	hröðum	hröðum
Genetive	hraðra	hraðra	hraðra

With the definite article

	Vyriška	Moteriška	Neutrali	Daugiskaita
Vardinis	hraði	hraða	hraða	hröðu
Akusatyvas	hraða	hröðu	hraða	hröðu
daiktavardis	hraða	hröðu	hraða	hröðu
Genityvas	hraða	hröðu	hraða	hröðu

Now let's look at the adjective for strong. Note how it is declined in mostly the same way as new, but there is only one -t at the end in neuter, nominative, singular and how in genetive, plural there is only one r for strong, but two for new.

	Vyriška	Moteriška	Neutrali
Vardinis	sterkur	sterk	sterkt
Akusatyvas	sterkan	sterka	sterkt
daiktavardis	sterkum	sterkrar	sterks
Genityvas	sterks	sterkrar	sterks

	Plural masculine	Plural feminine	Plurar neuter
Nominatyvas	sterkir	sterkar	sterk
Akusatyvas	sterka	sterkar	sterk
Datyvas	sterkum	sterkum	sterkum
Genetive	sterkra	sterkra	sterkra

With the definite article

	Vyriška	Moteriška	Neutrali	Daugiskaita
Vardinis	sterki	sterka	sterka	sterku
Akusatyvas	sterka	sterku	sterka	sterku
daiktavardis	sterka	sterku	sterka	sterku
Genityvas	sterka	sterku	sterka	sterku