Look on love as a game (3)
I believe the answer is:
loo
'a game' is the definition.
(historical card game)
'look on love' is the wordplay.
'look' becomes 'lo' (archaic exclamation meaning 'look!').
'on' says to put letters next to each other (in a down clue, letters appear on others).
'love' becomes 'o' (love means zero in tennis).
'lo'+'o'='LOO'
'as' is the link.
(Other definitions for loo that I've seen before include "Ladies, perhaps" , "bog" , "Toilet (informal)" , "In which one goes" , "Lavatory - old card game" .)