Be offended in speech about marriage (6)
I believe the answer is:
bridal
'about marriage' is the definition.
(bridal means relating to a marriage)
'be offended in speech' is the wordplay.
'be offended' becomes 'bridle' (bridle can mean to show offence or irritation).
'in speech' shows a homophone (sound like).
'bridle' is a homophone of 'BRIDAL'.
(Other definitions for bridal that I've seen before include "Hotel suite for newly-weds" , "Newly-wed" , "To do with wedding - perhaps a suite" , "Woman in White" , "Relating to a newly married woman" .)