Some patch I described for mask (4)
I believe the answer is:
hide
'mask' is the definition.
(thesaurus)
'some patch i described' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'HIDE' can be found hidden inside 'patch i described'.
'for' acts as a link.
(Other definitions for hide that I've seen before include "harbour" , "Keep under wraps" , "Secrete - animal skin" , "Tanned skin of an animal" , "Once told, hurried < to > conceal" .)