Notice groom making formal speech (7)
I believe the answer is:
address
'formal speech' is the definition.
'notice groom' is the wordplay.
'notice' becomes 'ad'.
'groom' becomes 'dress' ('dress' can be a synonym of 'groom').
'ad'+'dress'='ADDRESS'
'making' is the link.
(Other definitions for address that I've seen before include "Call" , "particular house" , "Treat" , "Speak to at home?" , "Attend" .)