delusion
/dɪˈl(j)uːzjən/
noun
Meaning
A false belief that is resistant to confrontation with actual facts.
The state of being deluded or misled, or process of deluding somebody.
"It is far better to grasp the universe as it really is than to persist in delusion, however satisfying and reassuring."
That which is falsely or delusively believed or propagated; false belief; error in belief.