1. jaded:
exhausted, weary, tired
2. jealous:
resentful, bitter, grudging, envious, covetous
3. judicious:
sensible, commonsensical, sound, sober, intelligent
4. juvenile:
young, youthful, minor, teenage(d), immature
5. keepsake:
memento, souvenir, token, reminder, remembrance
6. kickback:
rebate, refund, share, compensation, commission, percentage
7. killjoy:
spoilsport, damper, dampener, grouch, grump, malcontent
8. knack:
genius, intuition, talent, gift, talent, facility, skill
9. laborious:
arduous, burdensome, onerous, strenuous, gruelling
10. lackadaisical:
lethargic, languorous, languid, listless, lazy
11. lambaste:
beat, whip, scourge, flog, lash, maul, horsewhip
12. laudable:
praiseworthy, meritorious, creditable, admirable, outstanding
13. legendary:
fabled, storied, traditional; heroic, epic, mythic
14. lethargic:
lethargical, sluggish, slow, dull, heavy, lazy
15. ludicrous:
ridiculous, laughable, absurd, farcical, nonsensical
16. luscious:
delectable, delicious, mouth-watering, tasty, toothsome
17. luxurious:
opulent, sumptuous, grand, extravagant, lavish, magnificent