[au.tism] n (1912) 1: absorption in self-centered subjective mental activity (as daydreams, fantasies, delusions, and hallucinations) usu. accompanied by marked withdrawal from reality
2: a mental disorder originating in infancy that is characterized by self-absorption, inability to interact socially, repetitive behavior, and language dysfunction (as echolalia) -- au.tis.tic adj or n -- au.tis.ti.cal.ly adv