Notice protective garment for expert (7)
I believe the answer is:
advisor
'expert' is the definition.
(advisor is a kind of expert)
'notice protective garment' is the wordplay.
'notice' becomes 'ad'.
'protective garment' becomes 'visor'.
'ad'+'visor'='ADVISOR'
'for' is the link.
(Other definitions for advisor that I've seen before include "Mentor, counsel" , "Guide; VI roads (anag.)" , "one counsels" , "One giving counsel (O, not E)" , "consultant" .)