What is suck it up?

"Suck it up" is a colloquial expression that means to tolerate or endure something unpleasant without complaining. It is often used as an encouragement to be brave and deal with a difficult situation. The phrase can also be used to express frustration with somebody who is being overly sensitive or complaining about something trivial. Its origin comes from the sucking action made when drinking through a straw – it is similar to "take it in" or "deal with it".