Look with love at an exceptional leg (4)
I believe the answer is:
ogle
'look' is the definition.
(I know that ogle is a more specific form of look)
'love at an exceptional leg' is the wordplay.
'love' becomes 'o' (love means zero in tennis).
'at' is a charade indicator (letters next to each other).
'an exceptional' is an anagram indicator (an unusual or exceptional ordering of the letters).
'leg' anagrammed gives 'gle'.
'o'+'gle'='OGLE'
'with' acts as a link.
(Other definitions for ogle that I've seen before include "Eye up lasciviously" , "Eye greedily" , "View lecherously" , "Stare at lecherously" , "flirtatious look" .)