(idiomatic) You need to see something to believe it; visible facts cannot be denied. / (idiomatic) I am skeptical about your claim.

plural of true believer

Be assured; be certain. / Used other than figuratively or idiomatically: see believe, me.

alternative spelling of nonbeliever

someone who shares one's faith; a brother in faith

(childish) The quality or act of pretending; acting as if something is true when in fact one knows it is not.

(idiomatic, childish) To pretend or imagine.

The act of pretending that what is imaginary is real.

imaginary; conjured in someone's imagination, especially when imagined by a child

plural of non-believer