"anything of little use or value," late 14c., perhaps from a Scandinavian source (cf. Old Norse tros "rubbish, fallen leaves and twigs," Norwegian dialectal trask "lumber, trash, baggage," Swedish trasa "rags, tatters"), of unknown origin. Applied to ill-bred persons or groups from 1604 ("Othello"). Applied to domestic refuse or garbage in 1906 (American English).
"to discard as worthless," 1895, from trash (n.); in the sense of "destroy, vandalize" it is attested from 1970; extended to "criticize severely" in 1975. Related: Trashed; trashing.