Lover that was hardly hunky offers excuse (7)
I believe the answer is:
explain
'excuse' is the definition.
(excuse can mean to explain or justify)
'lover that was hardly hunky' is the wordplay.
'lover that was' becomes 'ex' (an ex-lover).
'hardly hunky' becomes 'plain' (plain can mean unattractive).
'ex'+'plain'='EXPLAIN'
'offers' is the link.
(Other definitions for explain that I've seen before include "Elucidate, make clear" , "Tell us how" , "Give reasons for" , "Resolve" , "Interpret" .)