Historical Slang for Your Edification and Amusement

From The Penguin Dictionary of Historical Slang, by Eric Partridge (which runs at 1000+ pages and is utterly fascinating), to smatter into NPC dialogue for that "authentic ye olden days" vibe. I chose a handful for each letter of the alphabet with the approximate dates of first usage according to the book. You could choose thousands more.

A
Abbey lubber - A lazy monk (1538-1750), a lazy, thriftless person (1750-1900)
Academician - A harlot (1760-1820). Ex academy, a brothel (late C. 17-18)
All wind and piss - Contemptuous (C. 19)
Avering - A boy's begging naked to arouse compassion (late C.17)
Avaunt, give the - Dismiss a person (C. 16-17)

B
Bachelor of law - A drinker (1650)
Bachelor's baby - An illegitimate child (1670)
Batty-fang - To beat (C.17)
Beggar-maker - A publican (C.18)
Beggar's velvet - Downy matter or fluff (C.19)

C
Chair-days - Old age (C. 19)
Chovey - A shop (C. 19)
Church-work - Work that proceeds very slowly (C. 17)
Clapper - The tongue (human) (C.17)
Cold cook - An undertaker (1720s)
Cunny-warren - A brothel (1785)

D
Dive in the dark - The act of coition [it actually says this] (C.19)
Dismais - In low spirits (1760)
Disguised - Drunk (C. 16)
Docked smack smooth, to be - To have one's penis amputated (C.18) [Be thankful you don't live at a time in which this was happening frequently enough to need a slang term]
Dusting - A thrashing; rough weather (C. 18)

E
Ebb-water - Lack of money (C. 17)
Earwig - A malicious prompter or flatterer; a crony (1610
Eve's custom-house - The female pudend [it actually says this] (C.18)
Execution day - Washing day (C.17)

F
Fair trader - A smuggler (C.19)
One of the faithful - A drunkard (C.17)
Fart-catcher - A footman or valet (mid-C.18)
Fingers made of lime-twigs, to have - To be a thief (1596)
Flying camp - A gang of beggars (Late C.17)

G
Gawk - A simpleton; a fool (C.17)
Gin-trap - The mouth; the throat (1827)
Glimmerer - A beggar alleging loss by fire (1560
Goats and monkeys (at), to look - To gaze lecherously (at) (1749)
Grin at the daisy-roots, to - To be dead (1880)

H
Hard neck - Extreme impudence (1870)
Hoddy-peak - A fool; a cuckold (1585)
Horn-thumb - A pickpocket (1565)
Howsomever - Nevertheless (1750
Hydromancy - The "study" of drink, i.e. alcoholism (1650)

I
Idea-box - Head (C.18)
Ivory-box - Mouth (1880)
Ivy-bush, like an owl in an - Having a large wig or very bushy hair (1606)

J
Jack Ketch's pippin - A candidate for the gallows (C. 18), also called a "Gallows apple"
Jelly-bag - The scrotum (C. 17)
Jug - A prison; to imprison; lock up (C.19)
Jump, see how the cat will - To watch the course of events before committing oneself (1820)

K
Keep back and belly - To clothe and feed (C.18)
Ken - A house or compound (1560)
Ken, crack a - To rob a house (late C.17)
Ken-crack lay - Housebreaking (C.17)
Ken-cracker - Housebreaker (C.17)
Key of the street, have the - To be shut out for the night or homeless (1835)
Kick the wind (or clouds) - To be hung (late C. 16)

L
Lay in water - To defer judgement (C.16)
Lion, as valiant as an Essex - Timid or fearful (C.18) [substituting "Essex" for a suitable location of your choice]
Loose fish - A person or irregular, esp. of dissipated habits (1827)
Lullaby - The male member (C.19)
Lump and bump - A fool; a simpleton (C.19)

M
Marriage face - A sad face (C.19)
Maunding cove - A beggar (C.17)
Maw-wallop - A filthy dish of food (C.18)
Maw-wormy - Captious; pessimistic (C.19)
Moon's man - A gypsy; a robber by night (C.16)

N
Nail - A person of an overreaching, imposing disposition (1812)
Napkin, take sheet and - To eat and sleep with someone or in some place (C.17)
Nasty man - A garrotter; the one in a garrotting gang who does the critical work (1840)
Night-flea - A boarder (C.19)
Number the waves - To engage in a pointless or time-wasting task (C.18)

O
Old man's milk - Whisky or other spirit (1860)
Otherguess - Different (C.16)
Oysters, drink to one's - To fare accordingly (esp. badly) (C.15)

P
Pad in the straw - A hidden dagger (C.15)
Peery - Sly (C.17)
Pickers and stealers - Hands (C.16)
Play the duck - To show oneself a coward (C.17)
Priggism - Thieving (1743)

Q
Queer duke - A decayed gentleman (C.17)
Quiet as a wasp in one's nose - Uneasy, restless (1670)
Quirklum - A puzzle (C.18)

R
Give green rats - To slander; to malign (1860)
Ride out - To become a highwayman (C.17)
Rise arse upwards - To be lucky (1670)
Rum dubber - A dextrous picklock (C.17)
Running snavel - A robber of children (C.18)

S
Safe as a crow in a gutter - Very safe (1630)
Satyr - Professional sheep-rustler (1714)
Secret - in the grand - Dead (1780)
Snail's gallop, go a - Go very slowly (1545)
Snub-devil - A clergyman (1780)

T
Tip the lion - To press a man's nose against his face and gouge his eyes out (1712)
Toad on a chopping block - Somebody sitting awkwardly, e.g. on a horse (C.17)
Tongue enough for two sets of teeth - To be very talkative (1786)
Topsail, pay one's debts with the - Got to sea having left debts unpaid (1785)
Town bull - A wencher or lady's man (C.17)

U
Umble-cum-stumble - To understand (C.19)
Upper storey - The head; the brain (C.18)
Useless as tits on a bull - Utterly useless (C.19)
Used up - Killed (C.18)

V
Vegetable breakfast - A hanging (C.19) [Because it's a "hearty choke" - geddit??]
Voyage of discovery - Going out stealing (C.19)
Virtue, to have one's [...] rewarded - To be imprisoned (1870)

W
Warming-pan - A bedfellow (C.17)
Waste, house of - A tavern or alehouse (1780)
Water in one's shoes - A source of annoyance (C.18)
Wedge-hunter - A thief specialising in silver plate and watches (C.19)
Well-fucked and far from home - To be very tired (C.19)

X, Y, Z
Yappy - Foolishly generous (C.19)
Yellow stockings, wear - To be jealous (C.17)