Month working in protective garment (5)
I believe the answer is:
apron
'protective garment' is the definition.
(apron is a kind of protective garment)
'month working' is the wordplay.
'month' becomes 'apr' (Apr is an example).
'working' becomes 'on'.
'apr'+'on'='APRON'
'in' is the link.
(Other definitions for apron that I've seen before include "Space in front of curtain" , "Protective cover" , "Area for aircraft not in use" , "something befitting kitchen-sink drama?" , "Kitchen garment or aerodrome strip" .)