action (n.)

mid-14c., accioun, "cause or grounds for a lawsuit," from Anglo-French accioun, Old French accion, action (12c.) "action; lawsuit, case," from Latin actionem (nominative actio) "a putting in motion; a performing, a doing; public acts, official conduct; lawsuit, legal action" (source also of Spanish accion, Italian azione), noun of action from past-participle stem of agere "to do" (from PIE root *ag- "to drive, draw out or forth, move").

Spelling with the restored Latin -t- begins in 15c. Meaning "active exertion, activity" is from late 14c. Sense of "something done, an act, deed" is late 14c. Meaning "military fighting" is from 1590s. Meaning "way in which (a firearm, etc.) acts" is from 1845. As a film director's command, it is attested from 1923.

The meaning "noteworthy or important activity" in a modern sense by 1933, as in the figurative phrase a piece of the action (by 1965), perhaps from a sense of action in card-playing jargon by 1914.

No "action" can be had on a bet until the card bet upon appears. If it does not appear after a turn has been made, the player is at liberty to change his bet, or to remove it altogether. Each bet is made for the turn only, unless the player chooses to leave it until he gets some action on it. [from "Faro" in "Hoyle's Games," A.L. Burt Company, New York: 1914]

But there are uses of action as far back as c. 1600 that seem to mean "noteworthy activity." The meaning "excitement" is recorded from 1968. In action "in a condition of effective operation" is from 1650s. Phrase actions speak louder than words is attested from 1731. Action-packed is attested from 1953, originally of movies.

updated on February 20, 2021

Definitions of action from WordNet
action (n.)
something done (usually as opposed to something said);
there were stories of murders and other unnatural actions
action (n.)
the state of being active;
he is out of action
Synonyms: activity / activeness
action (n.)
a military engagement;
he saw action in Korea
Synonyms: military action
action (n.)
a process existing in or produced by nature (rather than by the intent of human beings);
the action of natural forces
Synonyms: natural process / natural action / activity
action (n.)
the series of events that form a plot;
his novels always have a lot of action
action (n.)
the trait of being active and energetic and forceful;
a man of action
action (n.)
the operating part that transmits power to a mechanism;
the piano had a very stiff action
Synonyms: action mechanism
action (n.)
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;
Synonyms: legal action / action at law
action (n.)
an act by a government body or supranational organization;
recent federal action undermined the segregationist position
the United Nations must have the power to propose and organize action without being hobbled by irrelevant issues
the Union action of emancipating Southern slaves
action (n.)
the most important or interesting work or activity in a specific area or field;
gawkers always try to get as close to the action as possible
the action is no longer in technology stocks but in municipal bonds
action (v.)
institute legal proceedings against; file a suit against;
She actioned the company for discrimination
Synonyms: sue / litigate / process
action (v.)
put in effect;
He actioned the operation
Synonyms: carry through / accomplish / execute / carry out / fulfill / fulfil
From, not affiliated with etymonline.