Adj. (common).—1. Relating to thieves, their habits, customs, devices, lingo, etc.
1782. Geo. Parker, Humorous Sketches, p. 34. No more like a kiddy he’ll roll the flash song. [[10]]
1830. Lytton, Paul Clifford, ‘Long Ned’s Song.’ And rarely have the gentry flash, In sprucer clothes been seen.
1837. Dickens, Oliver Twist, ch. viii. I suppose you don’t know what a beak is, my flash com-pan-i-on.
1857. Snowden, Mag. Assistant, 3rd ed., p. 448. I have seen Cheeks (a flash name for an accomplice).
1863. C. Reade, Hard Cash, II., 244. He used some flash words, and they were shown into a public room.
1864. Cornhill Magazine, ii., 336. In the following verse, taken from a pet flash song, you have a comic specimen of this sort of guilty chivalry.
2. (thieves’).—Knowing; expert; showy. Cf., down, fly, wide-awake, etc. Hence (popularly), by a simple transition, vulgarly counterfeit, showily shoddy: possibly the best understood meanings of the word in latter-day English. To put one flash to anything = to put him on his guard; to inform.
1819. Moore, Tom Crib’s Memorial, p. 19. Another philosopher, Seneca, has shown himself equally flash on the subject.
1835. Dickens, Sketches by Boz, p. 17. Laying aside the knowing look, and flash air, with which he had repeated the previous anecdote.