Lower front of sister's hood (5)
I believe the answer is:
scowl
'lower' is the definition.
(scowling is a kind of lowering)
'front of sister's hood' is the wordplay.
'front of' suggests taking the first letters (the letter at the front of the word).
'hood' becomes 'cowl' (synonyms).
The initial letter of 'sisters' is 's'.
's'+'cowl'='SCOWL'
(Other definitions for scowl that I've seen before include "Angrily frown" , "Angry facial expression" , "Glower; frown" , "Grimace" , "Look threatening" .)