Use a sieve to keep the work flying (5)
I believe the answer is:
swift
'flying' is the definition.
(I've seen this before)
'use a sieve to keep the work' is the wordplay.
'use a sieve' becomes 'sift' (I've seen this before).
'to keep' indicates putting letters inside.
'the work' becomes 'w' (physics abbreviation).
'sift' enclosing 'w' is 'SWIFT'.
(Other definitions for swift that I've seen before include "Rapid - writer - bird" , "Swallow-like bird" , "A bird; Gulliver author" , "Happening quickly; author" , "Quick, prompt" .)