Definition

To mentally prepare or psyche oneself up for a challenge; also used as an exclamation to mean 'just kidding' or to feign a trick. As slang, 'psych' dismisses a previous statement as a joke.

Example Usage

He said he was quitting the team, but then shouted 'Psych!' when everyone reacted.

Origin

Short for psychology, popularized in American slang in the 1970s-80s.

Fun Fact

The 'psych-out' became a staple of playground culture and competitive sports as a psychological tactic.

Source: Definition backfill (hailey)