the act, state, of deluding or being deluded; a false opinion or belief, especially one that may be a symptom of madness

misconception, misbelief

a false or mistaken belief; false reasoning or argument

illusion, misconception

(an example, instance of) falsely making oneself appear to be virtuous or good

deceitfulness, pretence

a statement or conclusion that does not (seem to) have any connection to what was said or written before

fallacy

something done in order to deceive or done to make a person appear ridiculous; a practical joke; a feat of skill with the hands

deceit