difficult to penetrate; incomprehensible to one of ordinary understanding or knowledge; "the professor's lectures were so abstruse that students tended to avoid them"; "a deep metaphysical theory"; "some recondite problem in historiography"
crowded with or characterized by much activity; "a very busy week"; "a busy life"; "a busy street"; "a busy seaport"
actively or fully engaged or occupied; "busy with her work"; "a busy man"; "too busy to eat lunch"; "the line is busy"
(of facilities such as telephones or lavatories) unavailable for use by anyone else or indicating unavailability; (`engaged' is a British term for a busy telephone line); "her line is busy"; "receptionists' telephones are always engaged"; "the lavatory is in use"; "kept getting a busy signal"
overcrowded or cluttered with detail; "a busy painting"; "a fussy design"
keep busy with; "She busies herself with her butterfly collection"
requiring more than usually expected or thought due; especially great patience and effort and skill; "found the job very demanding"; "a baby can be so demanding"
culpably involved; "all those concerned in the bribery case have been identified"; "named three officials implicated in the plot"; "an innocent person implicated by circumstances in a crime"
resembling an oracle in obscurity of thought; "the oracular sayings of Victorian poets"; "so enigmatic that priests might have to clarify it"; "an enigmatic smile"
not clear to the understanding; "I didn't grasp the meaning of that enigmatic comment until much later"; "prophetic texts so enigmatic that their meaning has been disputed for centuries"
having more than one possible meaning; "ambiguous words"; "frustrated by ambiguous instructions, the parents were unable to assemble the toy"
having no intrinsic or objective meaning; not organized in conventional patterns; "an ambiguous situation with no frame of reference"; "ambiguous inkblots"
inspiring fear; "the formidable prospect of major surgery"; "a tougher and more redoubtable adversary than the heel-clicking, jackbooted fanatic"- G.H.Johnston; "something unnerving and prisonlike about high grey wall"
extremely impressive in strength or excellence; "a formidable opponent"; "the challenge was formidable"; "had a formidable array of compositions to his credit"; "the formidable army of brains at the Prime Minister's disposal"
uncertain as a sign or indication; "the evidence from bacteriologic analysis was equivocal"
open to two or more interpretations; or of uncertain nature or significance; or (often) intended to mislead; "an equivocal statement"; "the polling had a complex and equivocal (or ambiguous) message for potential female candidates"; "the officer's equivocal behavior increased the victim's uneasiness"; "popularity is an equivocal crown"; "an equivocal response to an embarrassing question"
open to question; "aliens of equivocal loyalty"; "his conscience reproached him with the equivocal character of the union into which he had forced his son"-Anna Jameson
not easy; requiring great physical or mental effort to accomplish or comprehend or endure; "a difficult task"; "nesting places on the cliffs are difficult of access"; "difficult times"; "a difficult child"; "found himself in a difficult situation"; "why is it so hard for you to keep a secret?"
requiring much effort and trouble; "the mountain climb was long, steep, and difficult"
having or appealing to those having worldly knowledge and refinement and savoir-faire; "sophisticated young socialites"; "a sophisticated audience"; "a sophisticated lifestyle"; "a sophisticated book"
marked by repeated turns and bends; "a tortuous road up the mountain"; "winding roads are full of surprises"; "had to steer the car down a twisty track"
involving the joint activity of two or more; "the attack was met by the combined strength of two divisions"; "concerted action"; "the conjunct influence of fire and strong wind"; "the conjunctive focus of political opposition"; "a cooperative effort"; "a united effort"; "joint military activities"