boring (part of speech: verb)
difficult (part of speech: adjective)
formidable, stressful, cumbersome, contrary, severe, arduous, knotty, demanding, harsh, oppressive, trying, thorny, tough, finicky, hard, fussy, tricky, difficult, uphill, toilsome, strenuous, wearying, complicated, complex, cantankerous, ticklish, rugged, burdensome, wearing, grinding, adverse, tight, laborious, rough, onerous, troublesome, bothersome
- An analogy is as good as a suggestion; it becomes wearisome when it is pressed too far. - "In-Darkest-England-and-the-Way-Out", Booth, William.
- The dust and heat made the day's journey very wearisome, but the prospect of seeing the wonderful valley made all hardships of little consequence. - "Eighty Years And More; Reminiscences 1815-1897", Elizabeth Cady Stanton.
- Campaigns are wearisome reading, but not the one that is pictured there. - "Imperial Purple", Edgar Saltus.