dup, v. — Green’s Dictionary of Slang

dup v.

[dub v.¹ or SE do up, although this would imply closing, unless the image is of fastening the door]

(UK Und.) to open (a door).

c.1566		implied in dup the jigger
c.1600		Shakespeare Hamlet IV v: Then up he rose, and donn’d his clothes, And dupp’d the chamber door.
1648		Dekker ‘Canters Dict.’ Eng. Villainies (9th edn).
1665		Head Eng. Rogue I 49: Dup, To enter.
c.1698		B.E. Dict. Canting Crew n.p.: Dup To enter or go into an house, As Dup the ken, Enter the House, Dup the Boozing-Ken, and booz a gage, go into the Alehouse and drink a pot.
1706		Coles Eng. Dict.
1719		A. Smith Lives of Most Notorious Highway-men, etc. (1926) 205: Dup, to enter, or open the door.
1725		New Canting Dict. [as cit. c.1698].
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict. [as cit. c.1698].
1754		Scoundrel’s Dict. 17: To enter a House – Dup.
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1811		Lex. Balatronicum.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.

dup the jigger (v.) (also dup the gibber, dup the gigger) [gigger n.¹/jigger n.¹ (1)]

(UK Und.) to open a door (cf. dub the gigg(er) under dub v.¹).

c.1566		Harman Caveat for Common Cursetours in Viles & Furnivall (1907) 84: dup the gyger to open the doore.
1592		Groundworke of Conny-catching n.p.: Tower ye, yonder is the ken, dup the giger and maunde that is beneship.
1608		Dekker Belman’s Second Nights Walk B2: If we [...] dup the giger of a Country coves Ken, to the quier cuffin we bing.
1610		Rowlands Martin Mark-all 38: Dup the gigger, open the doore.
1637		Dekker ‘Canting Song’ in Eng. Villainies (8th edn) O: [as cit. 1608].
1651		T. Randolph Hey for Honesty III i: I’ll stand the pad [...] Nip bungs, dupp gibbers leager, louse and bouse.
1674		‘The Beggars Curse’ Head Canting Academy (1674) 14: [as cit. 1608].
c.1698		B.E. Dict. Canting Crew n.p.: Dup the giger open the doore.

dup the ken (v.) [ken n.¹ (1)]

to enter a house.

c.1698		B.E. Dict. Canting Crew.
1719		A. Smith Lives of Most Notorious Highway-men, etc. (1926) 205: Dup the Ken, i.e., enter the house. Dup the boozing-ken, and booze a gage, i.e., go into the ale-house and drink a pot.