Filter fits awkwardly (4)
I believe the answer is:
sift
'filter' is the definition.
(as in sifting through something)
'fits awkwardly' is the wordplay.
'awkwardly' indicates anagramming the letters.
'fits' with letters rearranged gives 'SIFT'.
(Other definitions for sift that I've seen before include "Riddle, sieve" , "Sieve finely" , "Filter, riddle" , "Use fist to pass through perforated container" , "Winnow out" .)