Old English adjectives

case (nominative, genitive, dative, accusative and partly, instrumental).OE adjectives as well as OE nouns had two types of declension: strong and weak. An adjective was considered to be strong if neither demonstrative pronoun nor the definite article preceded it. Strong adjectives had vowel stems. Their stems coincided with those of nouns. An adjective was considered to be weak if there was either a demonstrative pronoun or the definite article before it. The strong declension of a-stem.

Old English adjectives

singular feminine and in the nominative and accusative plural neuter the ending -u-; those with a long root syllable have no ending at all in these forms. This difference is obviously due to rhythmical factors:
Singular Masculine Neuter Feminine
N blæc blæc blacu
G blaces blaces blæcre
D blacum blacum blæcre
A blæcne blæc blace
T blace blace -----
Plural
N blace blacu blaca
G blacra blacra blacra
D blacum blacum blacum
A blace blacu blaca

Monosyllabic adjectives

nouns, except in the genitive plural of all the genders, which often takes the ending -ra-, taken over from the strong declension.
Masculine Neuter Feminine Plural
N blaca blace blace blacan
G blacan blacan blacan blæcra
D blacan blacan blacan blacum
A blacan blace blacan blacan

The weak declension of adjectives

formed by means of the suffix -ra and the superlative degree was formed by means of the suffix -ost or -est: blæc - blæcra - blacost.In some cases while forming the degrees of comparison adjective suffered the influence of the i-umlaut: long - lengra - lengest.
Several adjectives have suppletive forms of comparative and superlative:
3õd - betera - betst ‘good’ lȳtel - læssa - læst ‘little’
micel - mãra - mæst ‘large’
yfel - wiersa - wierest ‘bad’
Almost of all the adjectives adverbs could be formed by adding the suffix -e: blæce. Adverbs as well as adjectives had two types of declension and were declined as adjectives.

Degrees of comparison of adjectives

degrees of comparison: positive, comparative and superlative. The comparative degree was formed from the positive with the help of the suffix –ra; the superlative degree was characterized with the suffix -est/ost. Sometimes suffixation was accompanied by an interchange of the root-vowel often caused by mutation (see Table 1).

Degrees of comparison of adjectives