tuneful vs melodious

tuneful and melodious both are adjectives.

Word	Noun	Adjective	Verb	Adverb
tuneful	No	Yes	No	No
melodious	No	Yes	No	No

As adjectives, tuneful and melodious are synonyms defined as:

tuneful and melodious: having a musical sound; especially a pleasing tune

tuneful (adjective)	melodious (adjective)
having a musical sound; especially a pleasing tune	containing or constituting or characterized by pleasing melody
	having a musical sound; especially a pleasing tune