Pocket found in short pants! (7)
I believe the answer is:
trouser
'pocket' is the definition.
(both can mean to steal or take)
'in short pants' is the wordplay.
'in short' means to remove the last letter.
'pants' becomes 'trousers' (synonyms).
'trousers' with its last letter taken away is 'TROUSER'.
'found' acts as a link.
(Other definitions for trouser that I've seen before include "For oneself" , "Appropriate" , "Pocket (something)" , "Pocket (slang)" , "Our rest (anag)" .)