make-believe

noun

1. pretense, especially of an innocent or playful kind; feigning; sham: the make-believe of children playing.
2. a pretender; a person who pretends.

adjective

3. pretended; feigned; imaginary; made-up; unreal: a make-believe world of fantasy.

n.“pretence,” 1811, from make (v.) + believe. As an adjective by 1824.