Despise blue watch straps (4,4,2)
I believe the answer is:
look down on
'despise' is the definition.
(synonyms)
'blue watch straps' is the wordplay.
I cannot really understand how this works, but
'blue' could be 'down' (both can mean sad) and 'down' is found within the answer.
'watch' could be 'lookon' (synonyms) and 'lookon' is found within the remaining letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Another definition for look down on that I've seen is " Disdain".)