To suck is to draw something by force. Vacuum cleaners suck dirt from the floor and milkshake drinkers suck this liquid, tasty liquid through a straw. The meaning of suck is to draw (something, such as liquid) into the mouth through a suction force produced by movements of the lips and tongue.

Phrasal verb suck up to someone (definition of suck from the cambridge academic content dictionary Β© cambridge university press) To draw into the mouth by producing a partial vacuum by action of the lips and tongue. See examples of suck used in a sentence. To draw (liquid) into the mouth by movements of the tongue and lips that create suction. To behave obsequiously; Sucking up to their rich relations.

To behave obsequiously; Sucking up to their rich relations.