HUMDRUM
humdrum, monotonous
(adjective) tediously repetitious or lacking in variety; “a humdrum existence; all work and no play”; “nothing is so monotonous as the sea”
commonplace, humdrum, prosaic, unglamorous, unglamourous
(adjective) not challenging; dull and lacking excitement; “an unglamorous job greasing engines”
monotony, humdrum, sameness
(noun) the quality of wearisome constancy, routine, and lack of variety; “he had never grown accustomed to the monotony of his work”; “he was sick of the humdrum of his fellow prisoners”; “he hated the sameness of the food the college served”
Source: WordNet® 3.1
Etymology
Adjective
humdrum (comparative more humdrum, superlative most humdrum)
Lacking variety or excitement; dull; boring.
Synonym: Thesaurus:boring
Noun
humdrum (countable and uncountable, plural humdrums)
(uncountable) The quality of lacking variety or excitement.
Synonyms: dullness, monotony
(countable, dated) A stupid fellow.
Source: Wiktionary
Hum"drum`, a.
Definition: Monotonous; dull; commonplace. "A humdrum crone." Bryant.
Hum"drum`, n.
1. A dull fellow; a bore. B. Jonson.
2. Monotonous and tedious routine.
Dissatisfied with humdrum. The Nation.
3. A low cart with three wheels, drawn by one horse.
Source: Webster’s Unabridged Dictionary 1913 Edition