adjective
unrealistic
Synonyms: abstract, absurd, chimerical, idealistic, illogical, impossible, impracticable, improbable, inapplicable, inefficacious, infeasible, inoperable, ivory-tower, no go, nonfunctional, nonviable, otherworldly, quixotic, romantic, speculative, starry-eyed, theoretical, unattainable, unbusinesslike, unfeasible, unreal, unserviceable, unusable, unwise, unworkable, useless, visionary, wild, won't fly
Antonyms: practical, sensible
adjective
unrealistic
Synonyms: abstract, absurd, chimerical, idealistic, illogical, impossible, impracticable, improbable, inapplicable, inefficacious, infeasible, inoperable, irrealizable, ivory-tower, no-go, nonfunctional, nonviable, not a prayer, otherworldly, out of the question, quixotic, romantic, speculative, starry-eyed, theoretical, unattainable, unbusinesslike, unfeasible, unreal, unserviceable, unusable, unwise, unworkable, useless, visionary, wild, won’t fly
Antonyms: practicable, practical, probable, realistic, reasonable, tenable, viable