Work in small personnel (5)
I believe the answer is:
screw
'work in' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'small personnel' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'personnel' becomes 'crew'.
's'+'crew'='SCREW'
Can you help me to learn more?
(Other definitions for screw that I've seen before include "Threaded pin" , "shot in pool hall" , "Prison officer - salary" , "little twister!" , "swerve" .)