To have any desire, idea, or plan that is unlikely to be realized; to imagine visionary projects or schemes; to have an idle fancy or a pipe dream; to daydream.
To form a mental image of something; to envision or create something in one's mind.
to assume
to use one's imagination
To believe in something created by one's own mind.
to conjecture or guess
Used to mock some idea.
A short fanfic or prompt placing a reader insert in a novel scenario with a character or celebrity.