The belief of one who considers himself the only being in existence.

metaphorical. The belief, on the part of an individual, that there is no proof that anything exists but his own mind; chiefly applied to…

(a) Metaphysics the reference of all things to one's own consciousness, egoism. (b) The frequent use of ‘I’, egotism of style.

Philosophy. The theory or belief that one's own self or consciousness is all that exists (more fully metaphysical solipsism) or all that can be…

An extreme form of subjective idealism, restricting reality to the perceiving self; solipsism.