Merriam-Webster Collegiate Dictionary - intelligent

 adjective  Etymology: Latin ~-, intelligens, present participle of intelligere, intellegere to understand, from inter- + legere to gather, select — more at legend  Date: 1509  1.  a. having or indicating a high or satisfactory degree of intelligence and mental capacity  b. revealing or reflecting good judgment or sound thought ; skillful  2.  a. possessing intelligence  b. guided or directed by intellect ; rational  3.  a. guided or controlled by a computer; especially using a built-in microprocessor for automatic operation, for processing of data, or for achieving greater versatility — compare dumb 7  b. able to produce printed material from digital signals an ~ copier  • ~ial adjective  • ~ly adverb Synonyms:  ~, clever, alert, quick-witted mean mentally keen or quick. ~ stresses success in coping with new situations and solving problems an ~ person could assemble it fast. clever implies native ability or aptness and sometimes suggests a lack of more substantial qualities clever with words. alert stresses quickness in perceiving and understanding alert to new technology. quick-witted implies promptness in finding answers in debate or in devising expedients in moments of danger or challenge no match for his quick-witted opponent.