Obsequious and silly chap isn't coy (11)
I believe the answer is:
Here is my best explanation:
'obsequious' is the definition.
('sycophantic' can be a synonym of 'obsequious')
'silly chap isn't coy' is the subsidiary indication.
'silly' is an anagram indicator.
'chapisntcoy' is an anagram of 'sycophantic'.
'and' is the link.
(Other definitions for sycophantic that I've seen before include "Fawning", "Servile, toadying", "Servile - like a crawler", "Toadying" and "Toadyish".)