Fixed sequin to pump (8)
I believe the answer is:
question
'pump' is the definition.
(I've seen this before)
'fixed sequin to' is the wordplay.
'fixed' is an anagram indicator.
'sequin'+'to'='sequinto'
'sequinto' is an anagram of 'QUESTION'.
(Other definitions for question that I've seen before include "Doubt; object to" , ""To be or not to be", for example" , "Interrogate or express doubt about" , "Inquiry" , "Grill" .)