white hope vs great white hope

white hope and great white hope both are nouns.

Word	Noun	Adjective	Verb	Adverb
white hope	Yes	No	No	No
great white hope	Yes	No	No	No

As nouns, white hope and great white hope are synonyms defined as:

white hope and great white hope: someone (or something) expected to achieve great success in a given field

white hope (noun)	great white hope (noun)
someone (or something) expected to achieve great success in a given field	someone (or something) expected to achieve great success in a given field