rook (n.1)

[European crow], Middle English roke, from Old English hroc, from Proto-Germanic *khrokaz (source also of Old Norse hrokr, Middle Dutch roec, Dutch roek, Middle Swedish roka, Old High German hruoh "crow"), probably imitative of its raucous voice. Compare crow (n.), also Gaelic roc "croak," Sanskrit kruc "to cry out." Used as a disparaging term for persons at least since c. 1500, and extended by 1570s to mean "a cheat," especially at cards or dice, also, later "a simpleton, a gull, one liable to be cheated" (1590s). For sense, compare gull (n.2).

rook (n.2)

[chess piece], c. 1300, roke, in chess, "one of the four pieces placed on the corners of the board," from Old French roc, Medieval Latin rocus, rochus, all from Arabic rukhkh, from Persian rukh, a name of unknown meaning, perhaps somehow related to the Indian name for the piece, rut, from Hindi rath "chariot." It was confused in Middle English with roc.

rook (v.)

"to defraud by cheating" (originally especially in a game), 1580s, probably from rook (n.1) in the "cheat" sense. Related: Rooked; rooking.

updated on September 28, 2021

Definitions of rook from WordNet
rook (n.)
(chess) the piece that can move any number of unoccupied squares in a direction parallel to the sides of the chessboard;
Synonyms: castle
rook (n.)
common gregarious Old World bird about the size and color of the American crow;
Synonyms: Corvus frugilegus
rook (v.)
deprive of by deceit;
Synonyms: victimize / swindle / goldbrick / nobble / diddle / bunco / defraud / scam / mulct / hornswoggle / short-change / con
From, not affiliated with etymonline.