The most common and most likely answer to this crossword clue is the 4 letter word WIRE
W
I
R
E
More clues leading to the result WIRE
- Association of women on message
- Message that was sent with passion
- Secret device used with indignation?
- Cable in Wiltshire, stripped of core
- Independent’s right to plug Guardian’s listening device
- Jam specialists concerned with dip
- Send a message with indignation
- Partner adopts recipe for strong line
- Caribbean engineers make communication
- Something carrying current and old message
Buddy explains!

The straight part
We know that "Send a message" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case send a message = wire.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does WIRE mean?
WIRE noun- Metal formed into a thin, even thread, now usually by being drawn through a hole in a steel die.
- A piece of such material; a thread or slender rod of metal, a cable.
- A metal conductor that carries electricity.
- A fence made of usually barbed wire.
- A finish line of a racetrack.
- A telecommunication wire or cable
- (by extension) An electric telegraph; a telegram.
- A hidden listening device on the person of an undercover operative for the purposes of obtaining incriminating spoken evidence.
- A deadline or critical endpoint.
- A wire strung with beads and hung horizontally above or near the table which is used to keep score.
- (usually in the plural) Any of the system of wires used to operate the puppets in a puppet show; hence, the network of hidden influences controlling the action of a person or organization; strings.
- (thieves' slang) A pickpocket who targets women.
- A covert signal sent between people cheating in a card game.
- A knitting needle.
- The slender shaft of the plumage of certain birds.
- To fasten with wire, especially with reference to wine bottles, corks, or fencing.
- To string on a wire.
- To equip with wires for use with electricity.
- To add something into an electrical system by means of wiring; to incorporate or include something.
- (usually passive) To fix or predetermine (someone's personality or behaviour) in a particular way.
- To send a message or monetary funds to another person through a telecommunications system, formerly predominantly by telegraph.
- To make someone tense or psyched up. See also adjective wired.
- To install eavesdropping equipment.
- To snare by means of a wire or wires.
- To place (a ball) so that the wire of a wicket prevents a successful shot.