Forme fruste

In medicine, a forme fruste (French, "crude, or unfinished, form"; pl., formes frustes) is an atypical or attenuated manifestation of a disease or syndrome, with the implications of incompleteness, partial presence or aborted state. The context is usually one of a well defined clinical or pathological entity, which the case at hand almost — but not quite — fits.

An opposite term in medicine, forme pleine — seldom used by English-speaking physicians — means the complete, or full-blown, form of a disease.