v. & n.
v. 1 tr. draw (a fluid) into the mouth by making a partial vacuum. 2 tr. (also absol.) a draw milk or other fluid from or through (the breast etc. or a container). b extract juice from (a fruit) by sucking. 3 tr. a draw sustenance, knowledge, or advantage from (a book etc.). b imbibe or gain (knowledge, advantage, etc.) as if by sucking. 4 tr. roll the tongue round (a sweet, teeth, one's thumb, etc.). 5 intr. make a sucking action or sound (sucking at his pipe). 6 intr. (of a pump etc.) make a gurgling or drawing sound. 7 tr. (usu. foll. by down, in) engulf, smother, or drown in a sucking movement.
n. 1 the act or an instance of sucking, esp. the breast. 2 the drawing action or sound of a whirlpool etc. 3 (often foll. by of) a small draught of liquor. 4 (in pl.; esp. as int.) colloq. a an expression of disappointment. b an expression of derision or amusement at another's discomfiture. give suck archaic (of a mother, dam, etc.) suckle. suck dry 1 exhaust the contents of (a bottle, the breast, etc.) by sucking. 2 exhaust (a person's sympathy, resources, etc.) as if by sucking. suck in 1 absorb. 2 = sense 7 of v. 3 involve (a person) in an activity etc. esp. against his or her will. suck up 1 (often foll. by to) colloq. behave obsequiously esp. for one's own advantage. 2 absorb.
[ OE sucan, = L sugere ]