dreamer ˈdriːmə/ noun 1. a person who dreams or is dreaming. 2. a person who is unpractical or idealistic. "a rebellious young dreamer" synonyms: fantasist, fantasizer, daydreamer; romantic, sentimentalist, romancer; idealist, impractical/unrealistic person, wishful thinker, pipe-dreamer, castle-builder, utopian, Don Quixote, Walter Mitty; visionary; rarereverist; archaicfantast