See preoccupied in Webster's New World Roget's A-Z Thesaurus II
adjective
Having one's thoughts fully occupied:
absorbed, deep, intent, rapt. Idiom: wrapped up in. See awareness, exciteSo lost in thought as to be unaware of one's surroundings:
absent, absent-minded, abstracted, bemused, distrait, faraway, inattentive. Idiom: a million miles away. See ability, awareness
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