flat monotone monotonic monotonous
flat%5:00:00:unmodulated:00 monotone%5:00:00:unmodulated:00 monotonic%5:00:00:unmodulated:00 monotonous%5:00:00:unmodulated:00
enoličen monoton
sounded or spoken in a tone unvarying in pitch
the owl's faint monotonous hooting