deadweight

As nouns the difference between lightweight and deadweight

is that lightweight is (boxing) a boxer in a weight division having a maximum limit of 135 pounds for professionals and 132 pounds for amateurs while deadweight is the largest weight of cargo a ship is able to carry; ie, the weight of a ship when fully loaded minus its weight when empty.

As adjectives the difference between lightweight and deadweight

is that lightweight is lacking in earnestness, ability, or profundity while deadweight is (sports|billiards|snooker|pool) describes a shot with exact, precise pace to leave the balls in the perfect position usually just touching a cushion or very close to another ball.

Dwt is likely misspelled.

Dwt has no English definition.

As a noun deadweight

is the largest weight of cargo a ship is able to carry; i.e, the weight of a ship when fully loaded minus its weight when empty.

As an adjective deadweight

is describes a shot with exact, precise pace to leave the balls in the perfect position. Usually just touching a cushion or very close to another ball.