UNCHALLENGING Antonyms

• characterized by effort to the point of exhaustion; especially physical effort

• taxing to the utmost; testing powers of endurance

• difficult to accomplish; demanding considerable mental effort and skill

• complicated in structure; consisting of interconnected parts

• a conceptual whole made up of complicated and related parts

• a compound described in terms of the central atom to which other atoms are bound or coordinated

• (psychoanalysis) a combination of emotions and impulses that have been rejected from awareness but still influence a person's behavior

• a whole structure (as a building) made up of interconnected or related structures

• difficult to analyze or understand

• difficult to analyze or understand

• requiring more than usually expected or thought due; especially great patience and effort and skill

• not easy; requiring great physical or mental effort to accomplish or comprehend or endure

• hard to control

• extremely impressive in strength or excellence

• inspiring fear

• having many complexly arranged elements; elaborate

• characterized by effort to the point of exhaustion; especially physical effort

• not given to gentleness or sentimentality

• physically toughened

• resistant to cutting or chewing

• someone who learned to fight in the streets rather than being formally trained in the sport of boxing

• an aggressive and violent young criminal

• a cruel and brutal fellow

• very difficult; severely testing stamina or resolution

• substantially made or constructed

• violent and lawless

• feeling physical discomfort or pain (`tough' is occasionally used colloquially for `bad')

• unfortunate or hard to bear

• making great mental demands; hard to comprehend or solve or believe