noun which may take the genitive case particle 'no'
imaginary; in one's imagination
Used to describe something that exists only in the mind, not in reality. Often modifies nouns with の.
That is an imaginary creature.
He was talking to an imaginary friend.
仮想 means 'virtual' or 'suppositional', often used in computing or hypothetical scenarios. 想像上 is more about mental imagery.
Compound of 想像 (imagination) + 上 (on, above), literally 'on imagination', meaning 'in the realm of imagination'.