loathsome vs offensive

loathsome is not a noun while offensive is a noun.

Word	Noun	Adjective	Verb	Adverb
loathsome	No	Yes	No	No
offensive	Yes	Yes	No	No

As adjectives, loathsome and offensive are synonyms defined as:

Other synonyms of loathsome include nauseating, nauseous, noisome, queasy, sickening, vile.

loathsome (noun)	offensive (noun)
	the action of attacking an enemy

loathsome (adjective)	offensive (adjective)
highly offensive; arousing aversion or disgust	unpleasant or disgusting especially to the senses
causing or able to cause nausea	causing anger or annoyance
	for the purpose of attack rather than defense
	morally offensive
	violating or tending to violate or offend against
	causing or able to cause nausea