a.; also 6 harduos. [f. L. ardu-us high, steep, difficult + -OUS.]

1

  1.  Lofty, high, steep, difficult to climb; also fig.

2

1713.  Steele, Guard., No. 20, ¶ 1. To forgive is the most arduous pitch human nature can arrive at.

3

1709.  Pope, Ess. Crit., 95. Those arduous paths they trod.

4

1831.  Macaulay, Boswell, Ess. (1854), I. 174/2. Knowledge at which Sir J. Newton arrived through arduous and circuitous paths.

5

  2.  Hard to accomplish or achieve; requiring strong effort; difficult, laborious, severe.

6

1538.  Starkey, England, 27. A mater … of grete dyffyculty and harduos.

7

1718.  Pope, Iliad, XIV. 523. An arduous battle rose around the dead.

8

1775.  Harris, Philos. Arrangem. (1841), 259. A task too arduous for unassisted philosophy.

9

1849.  Macaulay, Hist. Eng., I. 206. Such an enterprise would be in the highest degree arduous and hazardous.

10

  3.  By transference to the activity required for the task: Strenuous, energetic, laborious.

11

1753.  [See ARDUOUSLY].

12

1860.  Tyndall, Glac., I. § 22. 160. Less than two good ones [guides] … an arduous climber ought not to have.

13

1873.  Burton, Hist. Scot., VI. lxxiii. 376. Montrose made arduous efforts to reconstruct his army.

14