An impasse, too, could involve an advantage (5)
I believe the answer is:
asset
'an advantage' is the definition.
(I've seen this before)
'an impasse too could involve' is the wordplay.
'involve' says the answer is hidden in the clue (I've seen 'involves' mean this).
'ASSET' is hidden within 'impasse too could'.
(Other definitions for asset that I've seen before include "It's an advantage to declare" , "Useful item" , "Anything of value" , "Valuable possession, worth having" , "Part of motor vehicle wheel" .)