Definition of "dumb"

to unloose the very tongues even of dumb creatures

1594–1597, Richard Hooker, edited by J[ohn] S[penser], Of the Lawes of Ecclesiastical Politie, […], London: […] Will[iam] Stansby [for Matthew Lownes], published 1611, (please specify the page)

We are dumb and we would talk

1884 January 5, “Mighty maiden with a mission”, in W. S. Gilbert (lyrics), Arthur Sullivan (music), Princess Ida‎, performed by D'Oyly Carte Opera Company, London, page 48

Deaf and blind and dumb and born to follow / What you need is someone strong to guide you

1992, “Opiate”, performed by Tool

Since you are tongue-tied and so loath to speakIn dumb significants proclaim your thoughts

1591 (date written), William Shakespeare, “The First Part of Henry the Sixt”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act II, scene iv]

O let my books be then the eloquenceAnd dumb presagers of my speaking breast […]

1609, William Shakespeare, “Sonnet 23”, in Shake-speares Sonnets. […], London: By G[eorge] Eld for T[homas] T[horpe] and are to be sold by William Aspley

The country people frequently ſay,—How can you treat a poor dumb beaſt ill; and a ſtreſs is very properly laid on the word dumb; for dumb they appear to thoſe who do not obſerve their looks and geſtures; but God, who takes care of every thing, underſtands their language...

1788, Mary Wollstonecraft, chapter 2, in Original Stories from Real Life (Children's literature), London: J. Johnson, published 1796, pages 10–11

to pierce into the dumb past

1881, John Campbell Shairp, Aspects of Poetry

Her stern, which was painted of a dumb white or dun color.

1720, Daniel Defoe, The Life, Adventures and Piracies of the Famous Captain Singleton

[…] what I would have spokeWas beastly dumbed by him.

c. 1606–1607, William Shakespeare, “The Tragedie of Anthonie and Cleopatra”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act I, scene v]

The paralysis of the Northern conscience, the dumbing of the Northern voice, were coming to an end.

1911, Lindsay Swift, William Lloyd Garrison, page 272

I think she's dumbing us down, so we won't be smarter than her.

2003, Angela Calabrese Barton, Teaching Science for Social Justice, page 124

Bad-mouthing Neanderthals . . is symptomatic of a need to exclude and even demonize. . I suggest that the unproven dumbing of the Neanderthals is an example of the same cultural preconception.

2004, Stephen Oppenheimer, The Real Eve: Modern Man's Journey Out of Africa, page 107

The ensuing storm caused the department to lower the bar—amid protests that this was dumbing the test down—so that only 80 percent of urban kids would fail.

2002, Deborah Meier, In Schools We Trust: Creating Communities of Learning in an Era of Testing, page 126