| Justice | Just, Fairness | Female | English |
| Kahuna | | Unisex | |
| Kali | after the Indian goddess of death | Female | Sanskrit |
| Kelly | Lively: aggressive.
| Female | Irish |
| Khan | An Indian ruler or official | Unisex | |
| Killer | | Unisex | |
| Kodiak | Large Alaskan brown bear. | Female | Russian |
| Kujo | | Unisex | |
| Kyo | Approval, Ginger, Or Large | Unisex | Japanese |
| Liberty | Free
| Female | Word |
| Licorice | Confection made from the licorice root. | Unisex | |
| London | fierce ruler of the world | Female | English |
| Lumpy | | Unisex | Hebrew |
| Macho | | Unisex | Hebrew |
| Mafia | | Unisex | Hebrew |
| Magnum | A large type of wine bottle. | Unisex | |
| Majestic | | Unisex | Hebrew |
| Mako | | Unisex | Hebrew |
| Marble | | Unisex | |
| Marlboro | | Unisex | Hebrew |
| Maxi | Short for maximum - the greatest possible quantity | Female | |
| Maxine | greatest | Female | Latin |
| Medusa | Guardian | Unisex | Latin |
| Monster | A creature of frightening appearance | Unisex | |
| Moose | Largest member of the deer family. Moose have heavy brown bodies with humped shoulders and broad antlers. | Unisex | |