Wield a mop (4)
I believe the answer is:
swab
'wield a mop' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for swab that I've seen before include "Mop; surgical pad" , "Cleaning implement" , "Absorbent pad for cleansing or drying" , "Piece of fabric for medical use" , "Absorbent surgical pad" .)