untrue vs inconstant

untrue and inconstant both are adjectives.

Word	Noun	Adjective	Verb	Adverb
untrue	No	Yes	No	No
inconstant	No	Yes	No	No

untrue (adjective)	inconstant (adjective)
not according with the facts	likely to change frequently often without apparent or cogent reason; variable
(used especially of persons) not dependable in devotion or affection; unfaithful
not accurately fitted; not level
not true to an obligation or trust