potty (adj.)

"crazy, silly," 1916, slang, of unknown origin, perhaps connected to potter (v.). Earlier slang senses were "easy to manage" (1899) and "feeble, petty" (1860).

1942, child's word for "chamber pot," from pot (n.1). Potty-training is attested from 1958. Potty-mouth "one who uses obscene language" is student slang from 1968.