be a figment of (one's/the) imagination

be a figment of (one's/the) imagination

To be an imagined experience (especially after one has initially thought it to be real). I thought I heard the sound of my front door opening last night but it turned out to be a figment of my imagination.

See also: figment, imagination, of

Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.