Equal, but lighter (5)
I believe the answer is:
match
I believe this clue is a double definition.
'equal' is the first definition.
('match' can be a synonym of 'equal')
'lighter' is the second definition.
(match is a kind of lighter)
'but' is the link.
(Other definitions for match that I've seen before include "Alliance" , "of little use when floodlights fail?" , "Stick in a box?" , "You can have a love or shouting one" , "Lighter; contest" .)