Counsellor (7)
(Other definitions for adviser that I've seen before include "Counsellor, mentor" , "Counseller" , "subject's specialist consultant" , "Guide" , "ID saver (anag.)" .)
'counsellor' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for advisor that I've seen before include "Wise counsellor" , "One offers recommendations" , "Assistant" , "one counsels" , "One giving counsel (O, not E)" .)