Cut small facial hair (5)
I believe the answer is:
slash
'cut' is the definition.
(I know that cut can be written as slash)
'small facial hair' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'facial hair' becomes 'lash' (I've seen this in another clue).
's'+'lash'='SLASH'
(Other definitions for slash that I've seen before include "Drastically prune" , "Wee stroke < /" , "Greatly reduce (prices)" , "Oblique stroke" , "something between a month and a year" .)