Why is the ninth month called September?
"European crow," Old English hroc, from Proto-Germanic *khrokaz (cf. Old Norse hrokr, Middle Dutch roec, Dutch roek, Middle Swedish roka, Old High German hruoh "crow"), possibly imitative of its raucous voice (cf. Gaelic roc "croak," Sanskrit kruc "to cry out"). Used as a disparaging term for persons since at least c.1500, and extended by 1570s to mean "a cheat," especially at cards or dice.
chess piece, c.1300, from Old French roc, from Arabic rukhkh, from Persian rukh, of unknown meaning, perhaps somehow related to the Indian name for the piece, rut, from Hindi rath "chariot." Confused in Middle English with roc.
"to defraud by cheating" (originally especially in a game), 1590s, from rook (n.1) in some sense (e.g. "a gull, simpleton," but this is not attested until 17c.). Related: Rooked; rooking.
: Balcony seats for 40 bucks are a real rookverb
To cheat; defraud; gyp: who would rook them for two dollars (1577+)
[probably fr the thieving habits of the rook, which it shares with other corvine birds like the crow and magpie]