1.NounThe image-making power of the mind; the act of mentally creating or reproducing an object not previously perceived; the ability to create such images.
"Imagination is one of the most advanced human faculties."
2.NounParticularly, construction of false images; fantasizing.
"You think someone's been following you? That's just your imagination."
3.NounCreativity; resourcefulness.
"His imagination makes him a valuable team member."
4.NounA mental image formed by the action of the imagination as a faculty; something imagined.