Adjectives agree in gender to the nouns they specify.
The values feminine, masculine and common, i.e.
the same morphological form for the feminine and the masculine, are
pertinent to adjectives.
The value common can be seen as a multilabel whose semantics
is a ``disjunction" operation:
in fact, the value c is a macro for m 
f.
It is used for the lexicon encoding of
the series of the one-ending and invariant adjectives.
For these classes of adjectives, the gender can be decided only in the context on the basis of syntactic considerations, i.e. by observing the gender of the agreed noun: un professore imparziale, una camicetta rosa. Sometimes the context is not sufficient to solve the underspecification and the gender remains undecided: insegnanti capaci affollano quella scuola.