monotonous
adjectiveUK /məˈnɒtənəs/
US /məˈnɑːtənəs/
Something that is boring because it stays the same and never changes.
The drive across the flat desert was long and monotonous.
OTHER MEANINGS
2. Said or spoken in a flat, unchanging tone of voice.
He answered in a monotonous voice that made everyone sleepy.
3. Having little variation in pitch or loudness, as a sound.
The monotonous hum of the engine lulled the passengers to sleep.
4. Lacking variety in work or daily life, making it feel tiresome.
She quit the job because the monotonous tasks left her uninspired.