Disbelief or uncertainty (about something); (countable) a particular instance of such disbelief or uncertainty.
To be undecided about; to lack confidence in; to disbelieve, to question.
A person's internal state of being and involuntary physiological response to an object or a situation, based on or tied to physical state and sensory data.
A reaction by a non-human organism with behavioral and physiological elements similar to a person's response.