Sun, possibly most interesting part
I believe the answer is:
highlight
'most interesting part' is the definition.
(I've seen this before)
'sun possibly' is the wordplay.
I cannot really understand how this works, but
'sun possibly' could be 'light' (sun is a kind of light) and 'light' is present in the answer.
The remaining letters 'high' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for highlight that I've seen before include "Draw attention to - streak in hair" , "Main feature" , "Call attention to" , "Emphasize" , "Most interesting part" .)