(Latin: absence of sound; quiet, still)

Cave tibi cane muto, aqua silente. (Latin expression)
Translation: "Beware of the silent dog and still water."

A Latin idiom: "Stagnant water can poison you." "Silent dogs can bite." Some Romans believed that taciturn (uncommunicative) adversaries were more dangerous than the ones who made a lot of noise.

silence, silencing, silenced
1. The condition or quality of being or keeping still and silent.
2. The absence of sound; a period of time without speech or noise.
3. Refusal or failure to speak out.
4. The absence or omission of mention, comment, or expressed concern.
5. Concealment; secrecy.
6. To keep from expression, for example by threats or pressure.
7. Etymology: From Old French, silence, "absence of sound"; from Latin silentium, "being silent" from silens and silere, "to be quiet" or "to be still".
1. A person or thing that silences.
2. A device that muffles the noise of a firearm (gun).
3. Chiefly British, the muffler on an internal-combustion engine.
4. A device for reducing the noise emitted by a mechanism; especially, a gun or exhaust system.
1. Utterly quiet: lacking any noise or sound.
2. Not speaking or communicating at a particular time; especially, by choice.
3. Saying very little; not inclined to say much; such as, "the strong silent type".
4. Communicated without words or sound: "She rolled her eyes in silent disbelief."
5. Currently inactive or not operating; such as, a silent volcano.
6. A description of a letter that appears in a word but is not pronounced; for example, the k in "knight".
7. A reference to movies made without sound; especially, those made before 1927.
8. Not allowed to speak because of a religious vow of silence; a silent order of monks.
1. One appointed to keep silence and order in court.
2. Someone who is sworn not to divulge secrets of state.
1. Marked by absence of noise or sound; still.
2. Not inclined to speak; not talkative.
3. Unable to speak.
4. Refraining from speech.
5. Not voiced or expressed; unspoken: a silent curse; silent consent.
6. Inactive; quiescent: a silent volcano.
7. Linguistics: Having no phonetic value; unpronounced; such as, the silent b in subtle.
8. Having no spoken dialogue and usually no soundtrack; a reference to a motion-picture film.
9. Producing no detectable signs or symptoms; such as, a silent heart attack.
Not silenced.

Silence words. More silence-content words at these links: mute and tacit-.