monotonous
adj. B2 Upper Intermediate US //məˈnɑtənəs// UK //mənˈɒtənəs// mo·not·o·nous
adj. describing something that is very boring because it does not change or vary at all. You use this to talk about a job, a sound, or a pattern that feels the same every day.
adj. lacking variety or change; characterized by a single, unchanging pattern or sound. Often used to describe repetitive tasks or environments that fail to engage the senses.
The long drive on the highway was monotonous.
Working the same shift every day at the factory became so monotonous that he started looking for a new job.
The critic argued that the film's monotonous pacing and lack of narrative tension made it a difficult experience for even the most patient viewers.
From monotone + -ous.