humdrum
1. [ adjective ] not challenging; dull and lacking excitement
Synonyms: commonplace unglamourous unglamorous prosaic
Examples:

"an unglamorous job greasing engines"

Related terms: unexciting
2. [ adjective ] tediously repetitious or lacking in variety
Synonyms: monotonous
Examples:

"a humdrum existence all work and no play" "nothing is so monotonous as the sea"

Related terms: dull