Man in hysterics (4)
I believe the answer is:
eric
'man' is the definition.
(I've seen this before)
'in hysterics' is the wordplay.
'in' indicates the answer is hidden within the clue.
'ERIC' is hidden in the letters of 'hysterics'.
(Other definitions for eric that I've seen before include "Boy's name" , "--, or Little by Little (Dean Farrar)" , "..... the Red was Norwegian 10th Century exployer" , "-- Sykes; -- Idle" , "- Sykes, British comedian" .)