monotonous

adj.

[1]	humdrum , boring , tedious , dull , tiresome , humdrum , sleep-inducing , soporific , wearisome , wearying , tiring , monotonic , repetitious , prosaic , banal , dry , dry-as-dust , uninteresting , dreary , colourless , unexciting , run-of-the-mill , ordinary , commonplace , routine , uneventful , everyday , mechanical , banausic , (Colloq) ho-hum
[2]	flat , monotone , monotonic