Seek clever incomplete group first (6)
I believe the answer is:
Here is my best explanation:
'seek' is the definition.
'clever incomplete group first' is the wordplay.
'clever' becomes 'arch' (I've seen this before).
'incomplete' means to remove the last letter.
'group' becomes 'set' (set is a kind of group).
'first' is a charade indicator (letters next to each other).
'set' with its final letter taken away is 'se'.
'arch' put after 'se' is 'SEARCH'.