I will say almost everything is not allowed (7)
I believe the answer is:
illegal
'is not allowed' is the definition.
(I've seen this before)
'i will say almost everything' is the wordplay.
'i will' becomes 'ill' (I've seen this before).
'say' becomes 'eg'.
'almost' means to remove the last letter (most of the word but not all of it).
'everything' becomes 'all' (I've seen this before).
'all' with its last letter taken off is 'al'.
'ill'+'eg'+'al'='ILLEGAL'
(Other definitions for illegal that I've seen before include "Outlawed" , "Wrong" , "Criminal, illicit" , "Felonious" , "Black-market" .)