Maybe king due favour had tiff (5)
I believe the answer is:
rowed
'had tiff' is the definition.
Although both the answer and definition are past participle verbs, I cannot understand how they can define each other.
'maybe king due favour' is the wordplay.
I cannot really understand how this works, but
'king' could be 'r' (abbreviation for rex, king in Latin) and 'r' is present in the answer.
'due' could be 'owed' (synonyms) and 'owed' is found in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for rowed that I've seen before include "Sculled" , "Created a noisy squabble" , "Took part in regatta, perhaps" , "Was in Boat Race maybe" , "Used oars" .)