Lackluster :---> dullness,
Laconic :---> brief to the point.
Lament :---> wail, express sadness.
Lassitude :---> languor, weariness.
Latent :---> potential, dormant, secret
Latitude :---> scope
Laud :---> praise.
Lethargy :---> stupor.
Levee :--->stone embankment to prevent flooding.
Levity :---> lack of seriousness.
Linger :---> pause, procrastinate.
Litigation :---> engaging in a law suit
Log :---> record of day to day activities
Lucid :---> easily understood.
Luminous :---> shining, issuing light.