1823. Jon Bee, Dict. of the Turf, etc. They were invariably thieves and gamblers who used flash formerly; but other kinds of persons, now-a-day, who may be rippishly inclined, adopt similar terms and phrases, to evince their uppishness in the affairs of life. These gentlemen also consider all terms of art and of science as flash; … of course, those words and sayings which are appropriate to the turf, the ring, and field sports, are equally considered as flash by them, and the word has been applied (too generally we allow), to all this species of quid pro quo lingo.
3. (old).—See quot. and cf., with a Shaksperian gloss of flash = a burst of wit or merriment.
1748. T. Dyche, Dict. (5th ed.), flash (s.), also a boast, brag, or great pretence made by a spendthrift, quack, or pretender to more art or knowledge than he really has.
4. (old).—A showy swindler. (e.g., the Sir Petronel Flash of quot.); a blustering vulgarian.
1605. Marston, Jonson, and Chapman, Eastward Hoe! iv. 1. ‘Sir Petronel Flash, I am sorry to see such flashes come from a gentleman of your quality.’
1632. Shirley, Love in a Maze, i., 2. The town is full of these vainglorious flashes.
5. (old).—A peruke or perriwig.
1690. B. E., New Dict. of the Canting Crew, s.v.
1785. Grose, Dict. of the Vulgar Tongue. Rum flash, a fine long wig. Queer flash, a miserable weather-beaten caxon.
6. (common).—A portion; a drink; or go (q.v.). Cf., Flash of Lightning, sense 1.