1560s, "pantomime dramatic presentation," from dumb (adj.) + show (n.).
Entries linking to dumb-show
dumb adj.
Old English dumb, of persons, "mute, silent, refraining from speaking or unable to speak," from Proto-Germanic *dumbaz "dumb, dull," which is perhaps from PIE *dheubh- "confusion, stupefaction, dizziness," from root *dheu- (1) "dust, mist, vapor, smoke," also expressing related notions of "defective perception or wits." The -b has probably been silent since 13c. Related: Dumbly; dumber; dumbest. Of animals, "lacking in speech," hence "without intellect" (c. 1200).
The fork in meaning probably comes via the notion of "not responding through ignorance or incomprehension." The Old English, Old Saxon (dumb), Gothic (dumbs), and Old Norse (dumbr) forms of the word meant only "mute, speechless;" in Old High German (thumb) it meant both this and "stupid," and in Modern German this latter became the only sense (the sense of "mute, speechless" being expressed by stumm). Meaning "foolish, ignorant" was occasional in Middle English, but the modern use in this sense (since 1823) seems to be from influence of German dumm, especially in Pennsylvania German.
dumb-cake ..., n. A cake made in silence on St Mark's Eve, with numerous ceremonies, by maids, to discover their future husbands. [Century Dictionary]
Applied to silent contrivances, hence dumb-waiter. Dumb ox "stupid man" is by 1756; dumb-bunny "stupid person" is college slang from 1922; dumb blonde "woman seen as incapable of comprehending anything complicated" is by 1936.
show n.
c. 1300, sceu, schewe, "act of exhibiting to view," from show (v.).
The meaning "an elaborately prepared display or spectacle to entertain a crowd" is recorded by 1560s. That of "an exhibition of strange objects, trivial performances, etc." is by 1760, hence "any kind of public display or gathering" (by 1830). The sense of "entertainment program on radio" is by 1932, later of television.
The sense of "appearance put on with intention to deceive" is recorded from 1520s. That of "ostentatious display" is from 1713 (showy is from 1712). The meaning "third place in a horse race" is from 1925, American English (see the verb). In military slang, "battle," by 1892 (Kipling).
Show of hands "raising of hands as an indication of the sense of a meeting, etc." is attested from 1789; Phrase for show "for appearance's sake" is from c. 1700. Show business is attested from 1850; the short form show biz turns up in Billboard magazine by 1942. The actor's creed the show must go on (scil. despite difficulties or calamities) is attested from 1890. Show-stopper "act that wins so much applause as to pause the show" is by 1926; show trial for one likely prejudiced and pre-judged, but done nonetheless with great publicity, is attested by 1937.