| deadly |
| demanding(adjective, dull, tough, severe, difficult) |
| depressing(adjective, dull, hard, severe, offensive) |
| discouraging(adjective, hard, severe, offensive, distressing) |
| dusty(adjective, dull, simple, boring, tedious) |
| formidable(adjective, tough, severe, difficult, awkward) |
| grinding(adjective, tough, rough, difficult, heavy) |
| gruelling |
| lacklustre |
| pedestrian(adjective, dull, boring, routine, wretched) |
| plaguing |
| prosy(adjective, dull, boring, routine, tedious) |
| run-of-the-mill(adjective, simple, ordinary, familiar, natural) |
| sluggish(adjective, simple, slow, stupid, unintelligent) |
| stale(adjective, dull, simple, flat, stupid) |
| stodgy(adjective, dull, flat, stupid, dead) |
| strained |
| stuffy(adjective, dull, flat, excite, stupid) |
| taxing |
| tired(adjective, dull, rough, boring, painful) |