Adjectives of the Vowel Declension

73. Many adjectives follow the ο-declension, the masculine and feminine being alike, as with nouns. Here belong nearly all compound stems in -o.

74.

75. Still more adjectives have a stem in -ο for the masculine and neuter, and a stem in -ᾱ for the feminine.

76.

77.  a. The feminine singular has -ᾱ after -ε-, -ι-, or -ρ-, otherwise -η.

b. In the nominative and genitive plural the feminine is accented like the masculine, not as it would be in a noun

δίκαιαι, δικαίων

78.Some adjectives are declined now with, now without, a separate feminine. Especially in poetry the forms vary.