monotonous vs monotonic

monotonous and monotonic both are adjectives.

Word	Noun	Adjective	Verb	Adverb
monotonous	No	Yes	No	No
monotonic	No	Yes	No	No

As adjectives, monotonous and monotonic are synonyms defined as:

monotonous and monotonic: sounded or spoken in a tone unvarying in pitch

Other synonyms of monotonous include flat, monotone.

monotonous (adjective)	monotonic (adjective)
tediously repetitious or lacking in variety	of a sequence or function; consistently increasing and never decreasing or consistently decreasing and never increasing in value
sounded or spoken in a tone unvarying in pitch	sounded or spoken in a tone unvarying in pitch