DRAB (5 letters) The term DULL, MONOTONOUS can be summarized by two crossword solutions: HUMDRUM (7 letters) and DRAB (5 letters). Both words refer to something that is uninteresting, tedious, and lacking in variety. HUMDRUM is derived from the Middle English word HUMDRUM, which means 'MONOTONOUS' or 'DULL'. DRAB, on the other hand, is derived from the Middle English word drabbe, which means 'DULL' or 'somber'. Both words are often used to describe a boring or tedious situation.