Forgave former lover and swore to ignore king (7)
I believe the answer is:
excused
'forgave' is the definition.
(excusing is a kind of forgiving)
'former lover and swore to ignore king' is the wordplay.
I cannot really understand how this works, but
'former' could be 'ex' (prefix meaning former or onetime) and 'ex' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for excused that I've seen before include "Forgiven" , "Exonerated" , "Given permission to leave, or pardoned" , "Made allowances for" , "Overlooked offence or released from duty" .)