strenuous vs arduous

strenuous and arduous both are adjectives.

Word	Noun	Adjective	Verb	Adverb
strenuous	No	Yes	No	No
arduous	No	Yes	No	No

As adjectives, strenuous and arduous are synonyms defined as:

strenuous and arduous: taxing to the utmost; testing powers of endurance

Other synonyms of strenuous include straining.

strenuous (adjective)	arduous (adjective)
taxing to the utmost; testing powers of endurance	difficult to accomplish; demanding considerable mental effort and skill
characterized by or performed with much energy or force	characterized by effort to the point of exhaustion; especially physical effort
	taxing to the utmost; testing powers of endurance