light heavyweight:
(plural: ‘light heavyweights‘; pronunciation: the letters ‘i’ in ‘light’ and ‘weight’ rhyme with the word “eye”)
a boxer weighing between 160 and 170 pounds (about 76 and 80 Kg.) in boxing sport,

a light heavyweight boxer
Roshan, our national light heavyweight, is representing our country in the world light heavyweight contest in Brazil this year.
Though he weighed just under 170 pounds, Mack was the world’s light heavyweight for over four consecutive years.
There have been several light heavyweights who have become heavyweights before retiring from the ring.
heavyweight:
(plural: ‘heavyweights‘; pronunciation: ‘heavy…weight’)
a boxer who weighs about 200 pounds (about 90 Kg.),

boxing heavyweights
Of all the heavyweights, I like Ahmed Ali the greatest!
There are ‘heavyweights’ in other fighting related sports such as ‘kick boxing’, ‘free-style boxing’, and in ‘body-building’, etc., and the weight of the contestants differs slightly.
