means An intense but short-lived passion or fascination, usually built more on idealized fantasy than on real knowledge of its object.

from From Latin infatuare, 'to make a fool of,' built from in- (a strengthening prefix here) plus fatuus, 'foolish, silly, insipid' — the same root that gives us 'fatuous.' So at its core, to be infatuated is literally to be made foolish; the Romans baked the embarrassment right into the word.