OXFORD DICTIONARY
middleweight, n.
1 a weight in certain sports intermediate between welterweight and light heavyweight, in the amateur boxing scale 71-5 kg but differing for professionals, wrestlers, and weightlifters.
2 a sportsman of this weight.
junior middleweight
1 a weight in professional boxing of 66.7-69.8 kg.
2 a professional boxer of this weight.
light middleweight
1 a weight in amateur boxing of 67-71 kg.
2 an amateur boxer of this weight.
THESAURUS
middleweight
Chinese boxer, bantamweight, black belt, boxer, brown belt, bruiser, catchweight, featherweight, fighter, fisticuffer, flyweight, heavyweight, karate expert, light heavyweight, lightweight, palooka, prizefighter, pug, pugilist, savate expert, sparrer, welterweight