Is imagination a concrete noun

No, the noun 'imagination' is an abstract noun, a Word for an ability to form mental images of things that are not present to the senses; a Word for the formation of such images; a Word for a concept.

A concrete noun is a Word for something that can be experienced by any of the five physical senses; something that can be seen, heard, smelled, tasted, or touched.

An abstract noun is a Word for something that can't be experienced by any of the five physical senses.