silent

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Marked by absence of noise or sound; still: synonym: quiet.
• adjective Not inclined to speak; not talkative.
• adjective Not speaking or refraining from speech.
• adjective Not saying anything about a particular matter; making no mention.
• adjective Not voiced or expressed; unspoken.
• adjective Having no spoken dialogue and usually no soundtrack. Used of a film.
• adjective Linguistics Having no phonetic value; unpronounced.
• adjective Inactive; quiescent.
• adjective Producing no detectable signs or symptoms.
• noun A silent movie.

from The Century Dictionary.

• Not speaking, or making a noise with the voice; withholding or restraining vocal sounds; mute; dumb; speechless: as, a silent spectator; silent watchers.
• In a restricted use, not given to speaking; using; few words; not loquacious.
• Not speaking about some specified thing; withholding mention or statement; saying nothing; uncommunicative.
• Lacking authority or ability to speak, as about something of personal concern; not having a voice; disqualified for speech: as, a silent partner in a firm (see partner); the silent part of creation.
• Not uttered or expressed with the voice; unmarked by utterance or demonstrative speech; unspoken; unsounded: as, silent agony or endurance; silent opposition; a silent letter (see below).
• Free from or unattended by noise or sound; marked by stillness; quiet: as, silent woods; a silent assembly.
• Synonyms and Silent, Taciturn, Dumb, Mute. Silent expresses the fact of not speaking, taciturn the habitual disposition to refrain from speaking. Dumb strictly implies lack of the organs of speech, or defect in them, or lack of the power of speaking, while mute implies some special cause: hence deaf-mute is thought by many a better name than deaf-and-dumb person for one who does not speak on account of deafness; an idol is dumb, not mute. Under figurative extension mute, dumb, and silent are often used outside of the lines here indicated. In such freer use there is an advance in strength from silent, to mute and from mute to dumb: as, silent from abstraction; mute with astonishment; struck dumb with horror.
• noun A silent period.
• noun A short-circuit switch attached to an electric alarm, which when closed prevents the alarm from acting.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Free from sound or noise; absolutely still; perfectly quiet.
• adjective Not speaking; indisposed to talk; speechless; mute; taciturn; not loquacious; not talkative.
• adjective Keeping at rest; inactive; calm; undisturbed.
• adjective (Pron.) Not pronounced; having no sound; quiescent
• adjective rare Having no effect; not operating; inefficient.
• adjective See Dormant partner, under Dormant.
• noun rare That which is silent; a time of silence.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Free from sound or noise; absolutely still; perfectly quiet.
• adjective Not speaking; indisposed to talk; speechless; mute; taciturn; not loquacious; not talkative.
• adjective Keeping at rest; inactive; calm; undisturbed; as, the wind is silent. Parnell. Sir W. Raleigh.
• adjective pronunciation Not pronounced; having no sound; quiescent; as, "e is silent in fable."
• adjective Having no effect; not operating; inefficient.
• adjective technology Without audio capability.
• adjective Hidden, unseen, as a silent voter or silent partner.
• noun uncountable That which is silent; a time of silence.
• noun A silent movie

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective not made to sound
• adjective unable to speak because of hereditary deafness
• adjective failing to speak or communicate etc when expected to
• adjective implied by or inferred from actions or statements
• adjective having a frequency below or above the range of human audibility
• adjective marked by absence of sound