adj. & n.
adj. 1 (of a person, animal, garment, etc.) of below average weight. 2 of little importance or influence.
n. 1 a lightweight person, animal, or thing. 2 a a weight in certain sports intermediate between featherweight and welterweight, in the amateur boxing scale 57-60 kg but differing for professionals, wrestlers, and weightlifters. b a sportsman of this weight. junior lightweight 1 a weight in professional boxing of 57.1-59 kg. 2 a professional boxer of this weight.