n. 25B6; noun
(informal) a small-time crook : CRIMINAL, lawbreaker, offender, villain, delinquent, felon, convict, malefactor, culprit, wrongdoer; rogue, scoundrel, cheat, swindler, racketeer, confidence trickster; thief, robber, burglar; informal (old) lag, shark, con man, con, jailbird; N. Amer. informal hood, yardbird; Austral./NZ informal crim; Law malfeasant.
the crook of a tree branch : BEND, fork, curve, angle.
25B6; verb he crooked his finger and called the waiter : COCK, flex, bend, curve, curl.