smashing vs cracking

smashing and cracking both are nouns.

Word	Noun	Adjective	Verb	Adverb
smashing	Yes	Yes	No	No
cracking	Yes	Yes	No	No

As adjectives, smashing and cracking are synonyms defined as:

Other synonyms of smashing include bang-up, bully, corking, dandy, great, groovy, keen, neat, nifty, not bad, old, peachy, slap-up, swell.

smashing (noun)	cracking (noun)
the act of breaking something into small pieces	the act of cracking something
	a sudden sharp noise
	the process whereby heavy molecules of naphtha or petroleum are broken down into hydrocarbons of lower molecular weight (especially in the oil-refining process)

smashing (adjective)	cracking (adjective)
excellent	excellent