combination vs mixture

combination and mixture both are nouns.

Word	Noun	Adjective	Verb	Adverb
combination	Yes	No	No	No
mixture	Yes	No	No	No

As nouns, mixture is a hyponym of combination; that is, mixture is a word with a more specific, narrower meaning than combination:

combination (noun)	mixture (noun)
the act of combining things to form a new whole	the act of mixing together
the act of arranging elements into specified groups without regard to order	an event that combines things in a mixture
a collection of things that have been combined; an assemblage of separate parts or qualities	any foodstuff made by combining different ingredients
a group of people (often temporary) having a common purpose	a collection containing a variety of sorts of things
a sequence of numbers or letters that opens a combination lock	(chemistry) a substance consisting of two or more substances mixed together (not in fixed proportions and not with chemical bonding)
an alliance of people or corporations or countries for a special purpose (formerly to achieve some antisocial end but now for general political or economic purposes)
a coordinated sequence of chess moves