Jet.  A lawyer.  Autem jet; a parson.

Jew.  An over-reaching dealer, or hard, sharp fellow; an
  extortioner:  the brokers formerly behind St. Clement’s
  church in the Strand were called Jews by their brethren
  the taylors.

Jew.  A tradesman who has no faith, i.e. will not give credit.

Jew bail.  Insufficient bail:  commonly Jews, who for a
  sum of money will bail any action whatsoever, and justify,
  that is, swear to their sufficiency; but, when called on, are
  not to be found.

Jew’s eye.  That’s worth a Jew’s eye; a pleasant or agreeable
  sight:  a saying taken from Shakespeare.

Jibber the KIBBER.  A method of deceiving seamen, by
  fixing a candle and lanthorn round the neck of a horse,
  one of whose fore feet is tied up; this at night has the
  appearance of a ship’s light.  Ships bearing towards it, run
  on shore, and being wrecked, are plundered by the inhabitants. 
  This diabolical device is, it is said, practised by the
  inhabitants of our western coasts.

Jig.  A trick.  A pleasant jig; a witty arch trick.  Also a
  lock or door.  The feather-bed jig; copulation.

Jigger.  A whipping-post.  Cant.

Jilt.  A tricking woman, who encourages the addresses of
  a man whom she means to deceive and abandon.

Jilted. Rejected by a woman who has encouraged one’s
  advances.

Jingle boxes.  Leathern jacks tipped with silver, and
  hung with bells, formerly in use among fuddle caps. 
  Cant.

Jingle brains.  A wild, thoughtless, rattling fellow.

JINGLERS.  Horse cosers, frequenting country fairs.

Impost takers.  Usurers who attend the gaming-tables,
  and lend money at great premiums.

Impudent stealing.  Cutting out the backs of coaches,
  and robbing the seats.

Impure.  A modern term for a lady of easy virtue.

Inching.  Encroaching.

Indies.  Black Indies; Newcastle.

India wipe.  A silk handkerchief.

INDORSER.  A sodomite.  To indorse with a cudgel; to drub
  or beat a man over the back with a stick, to lay cane upon
  Abel.

INEXPRESSIBLES.  Breeches.

Inkle weavers.  Supposed to be a very brotherly set of
  people; ‘as great as two inkle weavers’ being a proverbial
  saying.

Inlaid.  Well inlaid; in easy circumstances, rich or well
  to pass.

Innocents.  One of the innocents; a weak or simple person,
  man or woman.

Inside and outside.  The inside of a **** and the outside
  of a gaol.

Job.  A guinea.