atonic vs unaccented

atonic and unaccented both are adjectives.

Word	Noun	Adjective	Verb	Adverb
atonic	No	Yes	No	No
unaccented	No	Yes	No	No

As adjectives, atonic and unaccented are synonyms defined as:

atonic (adjective)	unaccented (adjective)
(used of syllables) carrying no stress	(used of syllables) carrying no stress
characterized by a lack of tonus	(used of vowels or syllables) pronounced with little or no stress