expansion vs inflation

expansion and inflation both are nouns.

Word	Noun	Adjective	Verb	Adverb
expansion	Yes	No	No	No
inflation	Yes	No	No	No

As nouns, inflation is a hyponym of expansion; that is, inflation is a word with a more specific, narrower meaning than expansion:

expansion: the act of increasing (something) in size or volume or quantity or scope
inflation: the act of filling something with air

Other hyponyms of expansion include dilatation, dilation, distension, distention, stretching, magnification, extension.

expansion (noun)	inflation (noun)
the act of increasing (something) in size or volume or quantity or scope	the act of filling something with air
adding information or detail	lack of elegance as a consequence of being pompous and puffed up with vanity
a discussion that provides additional information	(cosmology) a brief exponential expansion of the universe (faster than the speed of light) postulated to have occurred shortly after the big bang
a function expressed as a sum or product of terms	a general and progressive increase in prices