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

misconception, misbelief

something which one seems to see or experience during sleep

illusion, vision

(of a person) led by imagination instead of reason and experience

imaginary, romantic

a feeling of desire, trust, confidence; to expect and desire something that is possible

longing; dream

(the seeing of) something that does not really exist; a false or impossible idea

false appearance; false belief

based on a false or impossible idea

deceptive

to think (about something)

think about seriously

(an instance, occasion, of) a condition of being lost in dreamy, pleasant thoughts

daydream