space cadet

名词noun

1. 1(originally and chiefly science fiction) A person in training to be a (generally military) astronaut.
2. 2(slang, derogatory) One who deals with reality in a way consistent with being under the influence of (or "spaced out on") drugs.
3. 3(slang, derogatory) One who forgets, daydreams, or otherwise is distracted from reality more often than most.