Not allowed (12)
'not allowed' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for taboo that I've seen before include "Not allowed, forbidden, proscribed" , "Socially prohibited" , "No-no" , "Inhibition based on social custom" , "Socially forbidden" .)
'not allowed' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for illegal that I've seen before include "Unlawful" , "Felonious" , "Wrong" , "Outlawed" , "Unauthorised" .)
(Another definition for inadmissible that I've seen is " Not to be tolerated".)