Strong declension

Most adjectives are declined like ríkur and langur. Adjective stems lose the final -d or -ð of a consonant cluster in the n sg, nom + acc (e.g. blindur $$am blint, harður $$am hart).

If the stem ends with a vowel + ð, the -ð is assimilated with the -t (e.g. glaður $$am glatt), while a vowel + dd is assimilated as -tt (e.g. saddur $$am satt).

Adjectives containing the tense vowels -á/-jó/-ú are declined as hár, while those ending in -ur are declined like fagur (e.g. bitur, dapur, digur, lipur, magur, snotur, vitur).

Adjectives ending in -ll and -nn (apart from gamall, einsamall, lítill, mikill, and adjectives (esp.past participles) ending in -inn) are declined like heill and beinn.

einsamall is declined like gamall. mikill is declined like lítill, but without changes in the vowel.

All adjectives with nom m sg ending in -ýr and -sær are declined like nýr, as is miður (f mið, n mitt) except that the nom m pl has the form miðjir.

Adjectives ending in -inn and the past participles of the strong verbs are declined like boginn, while the past participles of weak verbs with the ending -inn are declined like barinn (those that have -ð- in the preterite), like talinn (those that have -d- in the preterite), and like þakinn (those that have -t- in the preterite).

Weak declension

The weak form of the nom m sg is obtained by dropping the -r of the strong form of the nom m pl, e.g. langir > langi.

Comparatives are always inflected as weak adjectives (e.g. langur: all cases in m sg and f sg lengri, n sg lengra, pl (m, f, n) in all cases lengri.

Comparison

comp-ari, superl-astur.

The vast majority of adjectives form their comparatives and superlatives in this way.

comp-ri, superl-astur.

The comparative -r is assimilated and disappears in adjectives whose nom m sg ends in -ll or -nn such as heill. Adjectives ending in -legur/-ugur, -ull, and -á-, -é-, -í-, -ú-, -ý-, -æ-, -ei-, followed by -ll/-nn form their comparatives and superlatives as above.

comp-ri, superl-stur

Only a handful of adjectives form their comparatives and superlatives in this way.

A few comparatives and superlatives are derived from a separate stem: