Festival where everyone covers The Faces? (10)
I believe the answer is:
masquerade
I believe this is a double definition.
'festival' is the first definition.
(type of festival or celebration)
'where everyone covers the faces?' is the second definition.
(a masquerade is a masked ball)
(Other definitions for masquerade that I've seen before include "Dress up" , "Adam's queer? (anag)" , "Deception" , "False show - disguise oneself" , "Costume party" .)