imagine
To form a mental image of something; to envision or create something in one's mind.
To believe in something created by one's own mind, often something false.
To assume; to suppose.
To conjecture; to guess.
To use one's imagination.
(obsolete) To contrive in purpose; to scheme; to devise.
(sarcastic) {{n-g|Used to mock an idea by suggesting that it is ridiculous or ill thought through.}}
(fandom slang) A short fanfic or prompt placing a reader insert in a novel scenario with a character or celebrity.