Following cool former wife, play loose (7)
I believe the answer is:
inexact
'loose' is the definition.
('inexact' can be similar in meaning to 'loose')
'following cool former wife play' is the wordplay.
'following' is a charade indicator (letters next to each other).
'cool' becomes 'in' (I've seen this in other clues).
'former wife' becomes 'ex'.
'play' becomes 'act' ('act' can be a synonym of 'play').
'in'+'ex' is 'inex'.
'inex'+'act'='INEXACT'
(Other definitions for inexact that I've seen before include "Nice tax (nag.)" , "Not entirely accurate" , "Not precise, ambiguous" , "Rough" , "Lax" .)