What is "idiocrasy"

Idiocrasy \Id`i*oc"ra*sy\, n.; pl. Idiocrasies. [Idio- + Gr. kra^sis a mixture, fr. ? to mix: cf. F. idiocrasie.] Peculiarity of constitution; that temperament, or state of constitution, which is peculiar to a person; idiosyncrasy.

"peculiarity," 1680s, from Greek idiokrasia, from idio- (see idio-) + krasis "mixing, tempering" (see rare (adj.2)).