imbalance vs disproportion

imbalance and disproportion both are nouns.

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

As nouns, imbalance and disproportion are synonyms defined as:

imbalance and disproportion: lack of proportion; imbalance among the parts of something

Other synonyms of imbalance include dissymmetry.

imbalance (noun)	disproportion (noun)
lack of proportion; imbalance among the parts of something	lack of proportion; imbalance among the parts of something
a lack of balance or state of disequilibrium