SYN: Difficult, hard, lofty, onerous, laborious, steep, precipitous.
ANT: Easy, practicable, unlaborious, light, trivial.
=
KEY: Argue.
SYN: Discuss, debate, prove, question, evidence, establish, imply, sift, dispute, persuade, controvert, contend, demonstrate, reason.
ANT: Dictate, assert, propound, command.
=
KEY: Argument.
SYN: Reasoning, controversy, evidence, discussion, topic, dispute.
ANT: Assertion, assumption, without proof or evidence.