| Name | Meaning | Gender | Origin |
|---|
| Ignacio | Fiery | Male | Latin |
| Itsy | | Unisex | Hebrew |
| Jabba | | Unisex | Hebrew |
| Jack | God is gracious | Male | Hebrew |
| Jake | Supplanted | Male | Hebrew |
| Jaws | Bones that form the mouth. A dangerous situation - "The Jaws of Death" | Unisex | English |
| Jett | Black gemstone | Male | English |
| Jorge | Earth worker | Male | Greek |
| Junior | Younger | Male | English |
| Jupiter | Father god | Unisex | Latin |
| Kasper | Treasurer | Unisex | Persian |
| Kewpie | | Unisex | Hebrew |
| Kodiak | Island | Unisex | Russian |
| Kong | Empty, hollow, void | Male | Chinese |
| Lady | Lady | Unisex | English |
| Lil | Lily | Unisex | English |
| Lincoln | Lake settlement, lake colony | Male | English |
| Lobo | Wolf | Male | Spanish |
| Lou | Fame and war | Male | Germanic |
| Lucky | Fortunate | Unisex | English |
| Magnum | A large type of wine bottle. | Unisex | English |
| Mako | Child of truth | Unisex | Japanese |
| Manley | Common clearing | Male | English |
| Marco | From the god Mars | Male | Latin |
| Marmaduke | Devotee of Maedoc | Male | Gaelic |
| Marvel | Miracle | Unisex | English |
| Max | Little Maximus | Male | Latin |
| Maxi | Pet form of names starting with Max | Unisex | English |
| Mini | Something smaller than others of its type | Unisex | English |
| Munchkin | A very small elflike person. | Unisex | English |