whistleblower vs whistle blower

whistleblower and whistle blower both are nouns.

Word	Noun	Adjective	Verb	Adverb
whistleblower	Yes	No	No	No
whistle blower	Yes	No	No	No

As nouns, whistleblower and whistle blower are synonyms defined as:

whistleblower and whistle blower: an informant who exposes wrongdoing within an organization in the hope of stopping it

Other synonyms of whistleblower include whistle-blower.

whistleblower (noun)	whistle blower (noun)
an informant who exposes wrongdoing within an organization in the hope of stopping it	an informant who exposes wrongdoing within an organization in the hope of stopping it