whistle-blower vs informant

whistle-blower and informant both are nouns.

Word	Noun	Adjective	Verb	Adverb
whistle-blower	Yes	No	No	No
informant	Yes	No	No	No

As nouns, informant is a hypernym of whistle-blower; that is, informant is a word with a broader meaning than whistle-blower:

whistle-blower: an informant who exposes wrongdoing within an organization in the hope of stopping it
informant: a person who supplies information

Other hypernyms of whistle-blower include source.

whistle-blower (noun)	informant (noun)
an informant who exposes wrongdoing within an organization in the hope of stopping it	a person who supplies information
	someone who sees an event and reports what happened