imaginary
n.n. existing only in your mind or in a story, rather than in real life.
n. existing only in the imagination; lacking a basis in physical reality. In mathematics, it refers to a number whose square is negative.
The child has an imaginary friend named Leo.
The story takes place in an imaginary kingdom where magic is part of everyday life.
While the characters are based on historical figures, the dialogue and specific events in the novel are entirely imaginary, serving the author's thematic goals.
From Middle English ymaginarie, ymagynary, from Latin imāginārius (“relating to images, fancied”), from imāgō, equivalent to imagine + -ary. The mathematical sense derives from René Descartes's use (of the French imaginaire) in 1637, La Geometrie, to ridicule the notion of regarding non-real roots of polynomials as numbers. Although Descartes' usage was derogatory, the designation stuck even after the concept gained acceptance in the 18th century.
Typically placed before the noun it modifies. In social sciences, it can function as a noun ('the social imaginary') to describe shared cultural beliefs.
He is a very imaginative person.He is a very imaginary person.Learners often confuse 'imaginary' (not real) with 'imaginative' (having a creative mind).