facial expression vs facial gesture

facial expression and facial gesture both are nouns.

Word	Noun	Adjective	Verb	Adverb
facial expression	Yes	No	No	No
facial gesture	Yes	No	No	No

As nouns, facial expression and facial gesture are synonyms defined as:

facial expression and facial gesture: a gesture executed with the facial muscles

facial expression (noun)	facial gesture (noun)
the feelings expressed on a person's face	a gesture executed with the facial muscles
a gesture executed with the facial muscles