| juvenile | Characteristic of youth. |
| juxtapose | To place close together. |
| keepsake | Anything kept or given to be kept for the sake of the giver. |
| kerchief | A square of linen, silk, or other material, used as a covering for the head or neck. |
| kernel | A grain or seed. |
| kiln | An oven or furnace for baking, burning, or drying industrial products. |
| kiloliter | One thousand liters. |
| kilometer | A length of 1,000 meters. |
| kilowatt | One thousand watts. |
| kimono | A loose robe, fastening with a sash, the principal outer garment in Japan. |
| kind-hearted | Having a kind and sympathetic nature. |
| kingling | A petty king. |
| kingship | Royal state. |
| kinsfolk | pl. Relatives. |
| knavery | Deceitfulness in dealing. |
| knead | To mix and work into a homogeneous mass, especially with the hands. |
| knickknack | A small article, more for ornament that use. |
| knight errant | One of the wandering knights who in the middle ages went forth in search of adventure. |
| knighthood | Chivalry. |
| laborious | Toilsome. |
| labyrinth | A maze. |
| lacerate | To tear rudely or raggedly. |
| lackadaisical | Listless. |
| lactation | The secretion of milk. |
| lacteal | Milky. |
| lactic | Pertaining to milk. |
| laddie | A lad. |
| ladle | A cup-shaped vessel with a long handle, intended for dipping up and pouring liquids. |
| laggard | Falling behind. |
| landholder | Landowner. |
| landlord | A man who owns and lets a tenement or tenements. |
| landmark | A familiar object in the landscape serving as a guide to an area otherwise easily lost track of. |
| landscape | A rural view, especially one of picturesque effect, as seen from a distance or an elevation. |
| languid | Relaxed. |
| languor | Lassitude of body or depression. |
| lapse | A slight deviation from what is right, proper, or just. |
| lascivious | Lustful. |
| lassie | A little lass. |
| latent | Dormant. |
| latency | The state of being dormant. |
| later | At a subsequent time. |
| lateral | Directed toward the side. |
| latish | Rather late. |
| lattice | Openwork of metal or wood, formed by crossing or interlacing strips or bars. |
| laud | To praise in words or song. |
| laudable | Praiseworthy. |
| laudation | High praise. |
| laudatory | Pertaining to, expressing, or containing praise. |
| laundress | Washerwoman. |
| laureate | Crowned with laurel, as a mark of distinction. |