lightweight Definition

1. Light in weight.
2. derog
Having little importance or authority.
Thesaurus: unimportant, trivial, inconsequential, insignificant, trifling, negligible, petty, paltry; Antonym: weighty, serious.
3. Belonging to or relating to the lightweight class of boxing, etc.

1. A person or thing of little physical weight.
2. derog
A person or thing having little importance or authority.
3. A class for boxers, wrestlers and weight-lifters of not more than a specified weight (61.2kg (135lb) in professional boxing, different but similar weights in amateur boxing and the other sports).
4. A boxer, etc of this class.