Slogan from his new B&B shocked hotel (10)
I believe the answer is:
shibboleth
'slogan' is the definition.
(synonyms)
'his new bb shocked hotel' is the wordplay.
'new' is an anagram indicator.
'shocked' is an anagram indicator (I've seen this in other clues).
'his' anagrammed gives 'shi'.
'hotel' is an anagram of 'oleth'.
'shi'+'bb'+'oleth'='SHIBBOLETH'
'from' is the link.
(Other definitions for shibboleth that I've seen before include "Catchword, slogan" , "test word" , "cultural custom" .)