A prick of the conscience; a moral scruple, a pang of guilt.
A feeling of apprehension, doubt, fear etc.
A sudden sickly feeling; queasiness.
To have a sickly feeling.
The practice or philosophy of being a skeptic.
Doubt or disbelief of religious doctrines
The doctrine that absolute knowledge is not possible
A studied attitude of questioning and doubt
A methodology that starts from a neutral standpoint and aims to acquire certainty though scientific or logical observation.