- jobber
- juke-box
- jump
- karat
- keeping-room
- kerb
- jack
- jack light
- jackpot
- jaloppy
- jalopy
- jam
- janitress
- jay-walker
- jaywalk
- jelly-fish
- jeopard
- jerk
- jet set
- jibe
- jim crow
- jim-dandy
- jive
- job
- joe
- johnny-cake
- joiner
- junkman
- k-ration
- kale
- keen
- keno
- kerb-stone
- keyman
- killing
- jettison
- jim-jams
- jitters
- jobholder
- joint
- joker
- jollier
- jolt
- josh
- jugful
- juice
- julep
- junior
- junk
- junket
- kail
- kangaroo
- keep
- key
- keynoter
- kick
- kill
- kilometer
- kink
- kisser
- klansman
- kluxer
- knobbly
- kennel ration
- kept
- keyboard
- kickback
- kilter
- kip
- labor day
- lagniappe
- knife
- knives
- knob
- knock
- knock-about
- knocker
- kook
- kookie
- laid
- lam
- lamebrain
- lamp
- land office
- landslide
- lapidary
- latins
- leary
- lay
- lay-out
- lefty
- leg art
- lemon
- lawman
- lay-over
- leather-neck
- legman
- let
- levy
- liberty cap