Wiktionary
vb. 1 (context transitive original sense English) To outsmart. 2 (context transitive English) To unnerve.
Wikipedia
"Psych Out" is the 16th episode of the ninth season of the American police procedural drama NCIS, and the 202nd episode overall. It originally aired on CBS in the United States on February 21, 2012. The episode is written by Gary Glasberg & Reed Steiner and directed by Dennis Smith, and was seen by 19.29 million viewers.
In the episode, a Navy Reservist from Pentagon's Psy Ops division is shot during his own suicide, making Leroy Jethro Gibbs ( Mark Harmon) work with a psychiatrist to solve the case.
Usage examples of "psych out".
The Americans have better drugs, better computers to detect minor faults, better shrinks to psych out the athletes.
Okay, if that was part of a plan to psych out Tartaglia, it wasn't going to work.
I was taken on a tour of one of New York's more startling S&M bars once by Maureen Hooker, a farmer pro dominatrix (among many other skills), and I found it fascinating, trying to psych out all the different patrons, pick out the tops from the bottoms.
It was a standard ploy, one she'd often used herself to psych out an opponent.