adj. 25B6; adjective
a monotonous job : TEDIOUS, boring, dull, uninteresting, unexciting, wearisome, tiresome, repetitive, repetitious, unvarying, unchanging, unvaried, humdrum, routine, mechanical, mind-numbing, soul-destroying; colourless, featureless, dreary; informal deadly; Brit. informal samey; N. Amer. informal dullsville.
a monotonous voice : TONELESS, flat, uninflected, soporific.
interesting.