Synset

the quality of wearisome constancy, routine, and lack of variety
<noun.attribute>   freq. cnt.: 3 freq. cnt.: 3

humdrum

monotony

sameness

sample sentences

"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"