Arduous vs. Assiduous — What's the Difference?

Involving or requiring strenuous effort; difficult and tiring

Showing great care and perseverance

Demanding great effort or labor; difficult

Showing or characterized by persistent attention or untiring application

Testing severely the powers of endurance; strenuous

Hard-working, diligent or regular (in attendance or work); industrious.

Hard to traverse, climb, or surmount.

Constant in application or attention; devoted; attentive; unremitting.

Needing or using up much energy; testing powers of endurance.

Performed with constant diligence or attention; unremitting; persistent; as, assiduous labor.

(obsolete) burning; ardent

Marked by care and persistent effort;

Difficult or exhausting to traverse.

Steep and lofty, in a literal sense; hard to climb.

Attended with great labor, like the ascending of acclivities; difficult; laborious; as, an arduous employment, task, or enterprise.

Characterized by toilsome 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;