fever pitch vs fervour

fever pitch and fervour both are nouns.

Word	Noun	Adjective	Verb	Adverb
fever pitch	Yes	No	No	No
fervour	Yes	No	No	No

As nouns, fervour is a hypernym of fever pitch; that is, fervour is a word with a broader meaning than fever pitch:

Other hypernyms of fever pitch include excitation, excitement, fervor, inflammation.

fever pitch (noun)	fervour (noun)
a state of extreme excitement	feelings of great warmth and intensity
	the state of being emotionally aroused and worked up