work vs action

work and action both are nouns.

Word	Noun	Adjective	Verb	Adverb
work	Yes	No	Yes	No
action	Yes	No	Yes	No

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

work: activity directed toward making or doing something
action: the most important or interesting work or activity in a specific area or field

work (noun)	action (noun)
activity directed toward making or doing something	the most important or interesting work or activity in a specific area or field
the occupation for which you are paid	a judicial proceeding brought by one party against another; one party prosecutes another for a wrong done or for protection of a right or for prevention of a wrong
a product produced or accomplished through the effort or activity or agency of a person or thing	something done (usually as opposed to something said)
a place where work is done	a military engagement
the total output of a writer or artist (or a substantial part of it)	an act by a government body or supranational organization
applying the mind to learning and understanding a subject (especially by reading)	the operating part that transmits power to a mechanism
(physics) a manifestation of energy; the transfer of energy from one physical system to another expressed as the product of a force and the distance through which it moves a body in the direction of that force	In firearms terminology, the mechanism that handles the ammunition (loads, locks, fires, and extracts the cartridges).
	the trait of being active and energetic and forceful
	the series of events that form a plot
	a process existing in or produced by nature (rather than by the intent of human beings)
	the state of being active

work (verb)	action (verb)
give a workout to	put in effect
arrive at a certain condition through repeated motion	institute legal proceedings against; file a suit against
go sour or spoil
cause to undergo fermentation
find the solution to (a problem or question) or understand the meaning of
use or manipulate to one's advantage
to mix into a homogeneous mass
perform as expected when applied
move into or onto
shape, form, or improve a material
cause to happen or to occur as a consequence
prepare for crops
make something, usually for a specific function
gratify and charm, usually in order to influence
proceed along a path
move in an agitated manner
provoke or excite
be employed
cause to work
exert oneself by doing mental or physical work for a purpose or out of necessity; work
have an effect or outcome; often the one desired or expected
operate in a certain place, area, or specialty
proceed towards a goal or along a path or through an activity
have and exert influence or effect
operate in or through
cause to operate or function
behave in a certain way when handled