Lowers small hoods (6)
I believe the answer is:
scowls
'lowers' is the definition.
(scowling is a kind of lowering)
'small hoods' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'hoods' becomes 'cowls' ('cowl' can be a synonym of 'hood').
's'+'cowls'='SCOWLS'
(Other definitions for scowls that I've seen before include "Wrinkles forehead in disapproval" , "Bad-tempered frowns" , "Furrows forehead in bad humour" , "forbidding looks" , "Frowns with displeasure" .)