Doubt (11)
There are a few possibilities for this:
uncertainty
'doubt' is the definition.
(I know that doubt can be written as uncertainty)
This is all the clue.
(Other definitions for uncertainty that I've seen before include "suspicion" , "Doubt, scepticism" .)
'doubt' is the definition.
(I know that doubt is a kind of suspect)
This is the entire clue.
(Other definitions for suspect that I've seen before include "Imagine to be guilty" , "one on bail, perhaps" , "person in the dock" , "One is believed to be guilty but without proof" , "Funny" .)
'doubt' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for scruple that I've seen before include "A light-weight" , "Fine moral consideration" , "Weight (on one's conscience?)" , "carrying little weight" , "Objection" .)