Fit of pique unseemly (5)
I believe the answer is:
equip
'fit' is the definition.
(synonyms)
'pique unseemly' is the wordplay.
'unseemly' indicates an anagram.
'pique' is an anagram of 'EQUIP'.
'of' acts as a link.
(Other definitions for equip that I've seen before include "Give everything needed" , "Provide with requirements" , "Provide with stock" , "Provide everything that is required'" , "Supply with what is needed" .)