Definition of "suck up"

suck up

verb
third-person singular simple present sucks up, present participle sucking up, simple past and past participle sucked up
1. (transitive) To absorb (fluid).
2. (slang, often followed by to) To adulate or flatter (someone) excessively, generally to obtain some personal benefit or favour.
3. (slang) To fellate (someone).