monotonous (
http://definr.com/monotonous)
adj 1: sounded or spoken in a tone unvarying in pitch; "the owl's
faint monotonous hooting" [syn:
monotone,
monotonic]
2: tediously repetitious or lacking in variety; "a humdrum
existence; all work and no play"; "nothing is so
monotonous as the sea" [syn:
humdrum]