The story
The adjective and adverb are derived from un- (prefix meaning ‘not’) + together. The noun is probably derived from the adjective.
Etymology from Wiktionary, CC BY-SA 4.0.
untogether
un·to·geth·erToday it means: Not cohesive or united; disunited, disparate, separated; also, not coordinated; uncoordinated. Full definition →