MONOTONIC
flat, monotone, monotonic, monotonous
(adjective) sounded or spoken in a tone unvarying in pitch; “the owl’s faint monotonous hooting”
monotonic, monotone
(adjective) of a sequence or function; consistently increasing and never decreasing or consistently decreasing and never increasing in value
Source: WordNet® 3.1
Etymology
Adjective
monotonic (not comparable)
of or using the Greek system of diacritics which discards the breathings and employs a single accent to indicate stress. It replaced polytonic system in 1982.
(mathematics) said of a function that either never decreases or never increases as its independent variable increases.
Uttered in a monotone; monotonous.
Antonyms
• (using Greek system of diacritics): polytonic
Source: Wiktionary
Mon`o*ton"ic, Mon`o*ton"ic*al, a.
Definition: Of, pertaining to, or uttered in, a monotone; monotonous.
"Monotonical declamation." Chesterfield.
Source: Webster’s Unabridged Dictionary 1913 Edition