bag vs pouch

bag and pouch both are nouns.

Word	Noun	Adjective	Verb	Adverb
bag	Yes	No	Yes	No
pouch	Yes	No	Yes	No

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

As verbs, pouch is a hyponym of bag; that is, pouch is a word with a more specific, narrower meaning than bag:

bag (noun)	pouch (noun)
an activity that you like or at which you are superior	a small or medium size container for holding or carrying things
mammary gland of bovids (cows and sheep and goats)	(anatomy) saclike structure in any of various animals (as a marsupial or gopher or pelican)
a flexible container with a single opening	an enclosed space
a portable rectangular container for carrying clothes
a container used for carrying money and small personal items or accessories (especially by women)
a place that the runner must touch before scoring
an ugly or ill-tempered woman
the quantity that a bag will hold
the quantity of game taken in a particular period (usually by one person)

bag (verb)	pouch (verb)
put into a bag	swell or protrude outwards
capture or kill, as in hunting	put into a small bag
take unlawfully	send by special mail that goes through diplomatic channels
bulge out; form a bulge outward, or be so full as to appear to bulge
hang loosely, like an empty bag