ill-mannered vs rude

ill-mannered and rude both are adjectives.

Word	Noun	Adjective	Verb	Adverb
ill-mannered	No	Yes	No	No
rude	No	Yes	No	No

As adjectives, ill-mannered and rude are synonyms defined as:

Other synonyms of ill-mannered include bad-mannered, unmannered, unmannerly.

ill-mannered (adjective)	rude (adjective)
socially incorrect in behavior	lacking civility or good manners
	belonging to an early stage of technical development; characterized by simplicity and (often) crudeness
	socially incorrect in behavior
	(used especially of commodities) being unprocessed or manufactured using only simple or minimal processes
	(of persons) lacking in refinement or grace