Verb

1. To use the mouth to pull in liquid substances for ingestion or to perform a similar act on solid material without ingestion.
2. To draw into, by any means, with an attractive force, usually without direct contact. Used to describe the effect of negative pressure allowing atmospheric pressure to push air in, as occurs with breathing, drinking and vacuum cleaning.
3. To be inferior or objectionable: a general term of disparagement, sometimes used with at to indicate a particular area of deficiency.
   • 1970, Hunter S. Thompson, Fear and Loathing in America, Simon and Schuster, pg. 251:

     . . . and it has a few very high points . . . but as a novel, it sucks.

4. To perform fellatio; with off means to perform fellatio culminating in ejaculation.

Noun

1. A weak, self-pitying person; a person who won't go along, especially out of spite; a crybaby or sore loser.
   • 1999, Hiromi Goto, “Drift”, in Ms., v 9, n 3, p 82–6:

     “Why're you bothering to take her anywhere? I can't stand traveling with her. You're such a suck,” her sister said. Waved her smoke. “No fucking way I'm going.”

   • 2008, Beth Hitchcock, “Parenting Pair”, in Today's Parent, v 25, n 5, p 64:

     I used to think she was such a suck! She'd cry when I took to the ice, whether I skated well or badly. She'd cry when I left the house.

2. A sycophant, especially a child.
   • 1916, James Joyce, Portrait of the Artist as a Young Man, Macmillan Press, p 23:

     You are McGlade's suck.

Noun

1. sigh; a deep and prolonged audible inspiration or respiration