Catch short partner going west (6)
I believe the answer is:
entrap
'catch' is the definition.
(to entrap is to catch with a trap)
'short partner going west' is the wordplay.
'short' means to remove the last letter.
'going west' says the letters should be written backwards (letters heading to the west or left).
'partner' with its final letter taken away is 'partne'.
'partne' back-to-front is 'ENTRAP'.
(Other definitions for entrap that I've seen before include "Snare - inveigle" , "Capture" , "Take" , "Trepan (anag.)" , "Parent (anag)" .)