leitmotif vs melody

leitmotif and melody both are nouns.

Word	Noun	Adjective	Verb	Adverb
leitmotif	Yes	No	No	No
melody	Yes	No	No	No

As nouns, melody is a hypernym of leitmotif; that is, melody is a word with a broader meaning than leitmotif:

leitmotif: a melodic phrase that accompanies the reappearance of a person or situation (as in Wagner's operas)
melody: a succession of notes forming a distinctive sequence

Other hypernyms of leitmotif include air, line, melodic line, melodic phrase, strain, tune.

leitmotif (noun)	melody (noun)
a melodic phrase that accompanies the reappearance of a person or situation (as in Wagner's operas)	the perception of pleasant arrangements of musical notes
	a succession of notes forming a distinctive sequence