Suggestion - not one that's obvious (5)
I believe the answer is:
overt
'one that's obvious' is the definition.
(I've seen this in another clue)
'suggestion not' is the wordplay.
I cannot really see how this works, but
'not' could be 'o' (I've seen this in other clues) and 'o' is located in the answer.
The remaining letters 'vert' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for overt that I've seen before include "Obvious, patent" , "Plainly apparent" , "not disguised" , "totally visible" , "Open and obvious" .)