Look for a duck with a broken leg (4)
I believe the answer is:
ogle
'look' is the definition.
(ogling is a kind of looking)
'a duck with a broken leg' is the wordplay.
'a duck' becomes 'o'.
'with' is a charade indicator (letters next to each other).
'a broken' indicates an anagram.
'leg' is an anagram of 'gle'.
'o'+'gle'='OGLE'
'for' acts as a link.
(Other definitions for ogle that I've seen before include "Cast flirtatious glances at" , "Look at inappropriately" , "Eye flirtatiously" , "Amorous stare" , "flirtatious look" .)