Arduous

ar·du·ous play_w2(“A0413600″) (ärj-s)

adj.

1. Demanding great effort or labor; difficult: “the arduous work of preparing a Dictionary of the English Language” Thomas Macaulay.

2. Testing severely the powers of endurance; strenuous: a long, arduous, and exhausting war.

3. Hard to traverse, climb, or surmount. See Synonyms at burdensome, hard.