Not speaking; unable to speak. Also figurative.

Refraining from speech; keeping or observing silence; silent. Also, reticent, taciturn.

Of a person: lacking the power of speech; unable to speak owing to a congenital or pathological condition; dumb. (In quot. 1400 functioning as a…

That does not or will not speak; that remains persistently silent; little addicted to speech; taciturn, reticent.

Of a person: keeping or maintaining silence; refraining from or tending to refrain from speech or utterance; unable to speak.

Not noisy or talkative; not restless; restrained or disciplined in behaviour. Obsolete.

Of a person: †Reserved or reticent in conduct or conversation (obsolete); not given to indiscreet talking or the revelation of secrets; silent as…

of few words: not given to lengthy speaking, or to much speech; taciturn; laconic.

figurative. Restrained or debarred from speaking or free expression from any cause; speechless, mute, dumb, silent; also reticent, reserved.

colloquial. Strictly silent; mute; not saying a word. Esp. in to keep (also †play) mum: to remain silent, esp. so as not to reveal a secret…

Practising secrecy; reserved, reticent, uncommunicative; not open.

figurative. Of persons: Shut up within oneself, uncommunicative, morose, unsympathetic. Obsolete.

Not communicative; incommunicative.

Characterized by reticence or restraint in discourse or statement.

Not conversable; †unsociable (obsolete); not disposed to converse, uncommunicative.

Restrictive of oneself in expressing something; restrained in speech or behaviour; reticent; reserved. Now rare.

Not expressed in words; unspoken, unuttered.

Silent, mute; = mum, adj. Obsolete.

Uncommunicative. Obsolete. rare.

Resembling or suggestive of monks, their way of life, or their environment; austere, silent, secluded.

Constrained or limited in respect of words; esp. unable to use words freely or fluently. Now rare.

on (also upon) the reserve: (a) in a waiting attitude, in waiting; (b) reserved; reticent. Obsolete.

reticent, uncommunicative.

resembling an oyster; esp. (of a person) reserved or uncommunicative (staying inside one's ‘shell’).

Not communicative; not disposed for intercourse or conversation; uncommunicative.

Silent, mute; tongue-tied. Frequently in to sit (also stand,etc.) mumchance.

Marked or characterized by absence of speech; free from, unaccompanied or undisturbed by, speech.

= taciturn, adj.

= tongue-tied, adj. (literal and figurative).

Of a person: speaking in monosyllables; uttering few or brief words, esp. as indicative of a reluctance to engage in conversation.

Almost silent; very quiet.

(un-, prefix1 affix 1.)

Given to silence; taciturn, reticent.

Of a person: reluctant to reveal emotion or to express thoughts freely; reserved, inhibited, or formal in manner or disposition; unforthcoming…

Characterized by silence or disinclination to conversation; reserved in speech; saying little; uncommunicative.

Phrases: close as wax, tight as wax, neat as wax; to stick (to one) like wax; to fit like wax.

(un-, prefix1 affix 4.)

Reluctant or disinclined to speak out or express personal thoughts and feelings freely; reserved in speech; given to silence or concealment.

More generally: without a right or power to express feelings or opinions; silent.

In adjectives formed from the verb with an indefinite pronoun as object, as say-anything, say-nothing, etc., with the sense ‘that says —…

Not remonstrant.

Silent. Habitually silent, taciturn. Phrase, to keep a still tongue in one's head.

(un-, prefix1 affix 1.)

Not expansive.

Having a short tongue; hence (now dialect) inarticulate, stammering, lisping. Also occasionally taciturn, unready in speech.

Not offering access from one place, area of interest, etc., to another.

Having the lips firmly closed, esp. as a sign of determined suppression of emotion; also transferred and figurative. Also, determinedly reticent or…

Lacking words; silent. rare.

Quiet, silent. Frequently in to keep chup: to be quiet; to avoid talking about something secret or controversial, ‘to keep mum’.

having the lips tightly closed, esp. as a sign of suppressed emotion or determined reticence; (chiefly figurative) uncommunicative, determinedly…

Silent; quiet; not saying a word. Esp. in to keep (or stay) shtum.