monotonous monotonous /məˈnɑːtənəs/

adjective

1. () Tediously repetitious or lacking in variety  ( humdrum , monotonous )
   tediously repetitious or lacking in variety
    A humdrum existence; all work and no play
   a humdrum existence; all work and no play
    Nothing is so monotonous as the sea
   nothing is so monotonous as the sea
   
2. Sounded or spoken in a tone unvarying in pitch  ( flat , monotone , monotonic , monotonous )
   sounded or spoken in a tone unvarying in pitch
    The owl's faint monotonous hooting
   the owl's faint monotonous hooting