The most certain thing is that you breathe and the most uncertain thing is religion.
One is certain and the other in uncertain.
antonym: uncertain, unsure
uncertain
Uncertain
Uncertain.
uncertain
Not certain; not having certain knowledge; not assured in mind; distrustful., Irresolute; inconsonant; variable; untrustworthy; as, an uncertain person; an uncertain breeze., Questionable; equivocal; indefinite; problematical., Not sure; liable to fall or err; fallible., To make uncertain.
know
Certain and uncertain
Curtain, uncertain, certain, hurtin
certain Confident
A term Significant Figure refers to all the certain digits and one uncertain digit in a measurement.