Learning Greek

Adjectives
Adjectives decline, agreeing in case, number, and gender. Nominative singular male is the dictionary form. Most end –ος.
The general pattern is that adjectives decline the same way as the nouns. For example, όμορφος or beautiful:
Singular | Plural | ||||||
Masc. | Fem. | Neu. | Masc. | Fem. | Neu. | ||
Nom. | όμορφος | όμορφη | όμορφο | όμορφοι | όμορφες | όμορφα | |
Obj. | όμορφο | όμορφη | όμορφο | όμορφους | όμορφες | όμορφα | |
Gen. | όμορφου | όμορφης | όμορφου | όμορφων | όμορφων | όμορφων |
Adjectives with a vowel before the ending, like νέος or new, use –α in the feminine singular:
Singular | Plural | ||||||
Masc. | Fem. | Neu. | Masc. | Fem. | Neu. | ||
Nom. | νέος | νέα | νέο | νέοι | νέες | νέο | |
Obj. | νέο | νέα | νέο | νέους | νέες | νέα | |
Gen. | νέου | νέας | νέου | νέοων | νέεων | νέαων |
Some that end –κός or –χός use –ια for the feminine singular, although it seems that you can also use the usual –η.