Suspect (5)
'suspect' is the definition.
(synonyms)
This is all the clue.
(Other definitions for doubt that I've seen before include "Be uncertain about or consider unlikely" , "Have reservations or be uncertain about" , "Feel uncertain about" , "Uncertainty, unsureness" , "Disbelieve (someone)" .)
'suspect' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for mistrust that I've seen before include "Lack of belief (in someone)" , "Regard with suspicion" , "Suspect (someone)" , "Have no confidence in (someone)" , "reservations" .)