mission impossible vs mission

mission impossible and mission both are nouns.

Word	Noun	Adjective	Verb	Adverb
mission impossible	Yes	No	No	No
mission	Yes	No	No	No

As nouns, mission is a hypernym of mission impossible; that is, mission is a word with a broader meaning than mission impossible:

Other hypernyms of mission impossible include charge, commission.

mission impossible (noun)	mission (noun)
an extremely dangerous or difficult mission	a special assignment that is given to a person or group
	an operation that is assigned by a higher headquarters
	the organized work of a religious missionary
	a group of representatives or delegates
	an organization of missionaries in a foreign land sent to carry on religious work