The most common and most likely answer to this crossword clue is the 4 letter word MUTE
I've seen this crossword clue in The Daily Telegraph
M
U
T
E
More clues leading to the result MUTE
- Silent Greek character outside of Thule
- Silent writer outside extremely upset
- Mounties oddly silent
- Dumb letter to Greece by Lawrence
- Silencer Mike put on Victorian pick-up
- Mounties regularly struck dumb
- Silence as change? No thanks!
- Silent character with terrible clothes
- Silent figure among commuters
- Silent Greek character, note
Buddy explains!

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 MUTE mean?
MUTE noun- A stopped consonant; a stop.
- An actor who does not speak; a mime performer.
- A person who does not have the power of speech.
- A hired mourner at a funeral; an undertaker's assistant.
- An object for dulling the sound of an instrument, especially a brass instrument, or damper for pianoforte; a sordine.
- An electronic switch or control that mutes the sound.
- A mute swan.
- To silence, to make quiet.
- To turn off the sound of.
- Not having the power of speech; dumb.
- Silent; not making a sound.
- Not uttered; unpronounced; silent; also, produced by complete closure of the mouth organs which interrupt the passage of breath; said of certain letters.
- Not giving a ringing sound when struck; said of a metal.
- The faeces of a hawk or falcon.
- Of a bird: to defecate.
- To cast off; to moult.