Use a face covering in conversation (5)
I believe the answer is:
avail
'use' is the definition.
(I know that avail is a more specific form of the action exploit)
'a face covering in conversation' is the wordplay.
'face covering' becomes 'veil' (I've seen this before).
'in conversation' indicates a 'sounds like' (homophone) clue.
'veil' is a homophone of 'vail'.
'a'+'vail'='AVAIL'
(Other definitions for avail that I've seen before include "See 3" , "Use to one's advantage" , "(Of no) use or benefit" , "Provide help; profit" , "Serve a purpose" .)