opening vs mouth

opening and mouth both are nouns.

Word	Noun	Adjective	Verb	Adverb
opening	Yes	Yes	No	No
mouth	Yes	No	Yes	No

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

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

opening: an aperture or hole that opens into a bodily cavity
mouth: the externally visible part of the oral cavity on the face and the system of organs surrounding the opening

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

opening (noun)	mouth (noun)
a recognized sequence of moves at the beginning of a game of chess	the opening of a jar or bottle
the act of opening something	the externally visible part of the oral cavity on the face and the system of organs surrounding the opening
becoming open or being made open	the opening through which food is taken in and vocalizations emerge
the first of a series of actions	an impudent or insolent rejoinder
a vacant or unobstructed space that is man-made	the point where a stream issues into a larger body of water
an entrance equipped with a hatch; especially a passageway between decks of a ship	an opening that resembles a mouth (as of a cave or a gorge)
an aperture or hole that opens into a bodily cavity	a person conceived as a consumer of food
a possible alternative	a spokesperson (as a lawyer)
the initial part of the introduction
the first performance (as of a theatrical production)
a ceremony accompanying the start of some enterprise
an open or empty space in or between things
opportunity especially for employment or promotion

opening (adjective)	mouth (adjective)
first or beginning

opening (verb)	mouth (verb)
	express in speech
	articulate silently; form words with the lips only
	touch with the mouth