Light

1. Having little or relatively little actual weight; not cumbrous or unwieldy.
2. Having little weight as compared with bulk; of little density or [specific gravity]
3. Of short or insufficient weight; weighing less than the legal, standard or proper amount; clipped or diminished.
4. Lacking that which burdens or makes heavy.
   1. Free from burden or impediment; unencumbered.
   2. Lightly built; typically designed for speed or small loads.
   3. (military) Not heavily armed; armed with light weapons.
   4. (nautical, of a ship) Riding high because of no cargo; by extension, pertaining to a ship which is light.
   5. (rail transport, of a locomotive or consist of locomotives) Without any piece of equipment attached or attached only to a caboose.
   6. With low viscosity
5. (cooking) Not heavy or soggy; spongy; well raised.
6. Gentle; having little force or momentum.
7. Easy to endure or perform.
8. Low in fat, calories, alcohol, salt, etc.
9. Unimportant, trivial, having little value or significance.
10. (obsolete) Unchaste, wanton.
11. Not encumbered; unembarrassed; clear of impediments; hence, active; nimble; swift.
12. (dated) Easily influenced by trifling considerations; unsteady; unsettled; volatile.
13. Indulging in, or inclined to, levity; lacking dignity or solemnity; frivolous; airy.
14. Not quite sound or normal; somewhat impaired or deranged; dizzy; giddy.

Synonyms

• (of little weight):
• (lightly-built): lightweight
• (having little force or momentum): delicate, gentle, soft
• (low in fat, calories, etc): lite, lo-cal (low in calories), low-alcohol (low in alcohol)
• (having little value or significance): inconsequential, trivial, unimportant

Antonyms

• (of little weight): heavy, weighty, burdensome
• (lightly-built): cumbersome, heavyweight, massive
• (having little force or momentum): forceful, heavy, strong
• (low in fat, calories, etc): calorific (high in calories), fatty (high in fat), strong (high in alcohol)
• (having little value or significance): crucial, important, weighty