Third-person singular present tense of fantasize; to imagine or daydream about something that isn't real or likely to happen.
From fantasy (itself from Greek phantastikos meaning 'of imagination') plus the suffix -ize meaning 'to make or become.' The verb form developed in the 1800s as people needed a way to describe the act of engaging in fantasy.
Fantasizing is actually how our brains rehearse for the future—neuroscientists have found that imagining winning a game activates similar brain regions as actually playing it, which is why visualization training works in sports.
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