shrink

Where it comes from

Shrink is an old verb for contracting or drawing back. Its slang use for a psychiatrist or psychologist is a clipping of headshrinker, a term first used literally for a person said to shrink human heads and later applied, usually disparagingly or humorously, to mental-health professionals.

How the meaning developed

The psychiatric headshrinker appears in mid-twentieth-century American usage; a 1950 example calls it Hollywood jargon. The shorter shrink is documented in print by 1965. Explanations based on shrinking egos or problems are later guesses, not an established origin.