Forbidden steak occasionally, signalled displeasure (7)
I believe the answer is:
tabooed
'forbidden' is the definition.
(thesaurus)
'steak occasionally signalled displeasure' is the wordplay.
'occasionally' indicates alternate letters (letters taken at regular intervals or occasions).
'signalled displeasure' becomes 'booed' (I can't justify this - if you can you should believe this answer much more).
The alternating letters of 'steak' are 'ta'.
'ta'+'booed'='TABOOED'
Can you help me to learn more?
(Other definitions for tabooed that I've seen before include "Banned" , "Prevented" .)