imbalance vs unbalance

imbalance and unbalance both are nouns.

Word	Noun	Adjective	Verb	Adverb
imbalance	Yes	No	No	No
unbalance	Yes	No	Yes	No

As nouns, imbalance and unbalance are synonyms defined as:

Other synonyms of imbalance include instability.

imbalance (noun)	unbalance (noun)
lack of proportion; imbalance among the parts of something	a lack of balance or state of disequilibrium
a lack of balance or state of disequilibrium	a state of mental disturbance and disorientation

imbalance (verb)	unbalance (verb)
	derange mentally, throw out of mental balance; make insane
	throw out of balance or equilibrium