Former lover sat naked (7)
I believe the answer is:
exposed
'naked' is the definition.
(I've seen this before)
'former lover sat' is the wordplay.
'former lover' becomes 'ex'.
'sat' becomes 'posed' ('pose' can be a synonym of 'sit').
'ex'+'posed'='EXPOSED'
(Other definitions for exposed that I've seen before include "Made known" , "in the nude" , "Uncovered, visible" , "Not hidden" , "Unprotected from the weather" .)