As any learner of the Greek language will know, the gender of words in Greek is a critical issue. Adjectives agree with the gender and case of the noun they describe, and with three different genders and three different cases there are a multiplicity of endings for the student to remember. In addition there are several different adjectival forms with different endings. The most common are the form: -os (m), -i (f), -o (n), (e.g. “good”: kalos, kali, kalo), and the form: -is (m), -i (f)), -es (n), (e.g. “unstable”: astathis, astathi, astathes); but there are many other less common forms, e.g. for adjectives ending in -ios or -on in the masculine, and irregular forms of the -os and -is adjectives which depart from the general rule in the feminine and neuter cases.