A particular weight class, or member of such, as prescribed by the rules, between that of the heavier welterweight and the lighter featherweight. See Wikipedia for the specifics of each sport.

A particular weight category as prescribed by the rules, separate from an open or heavyweight class.

A competitive weight division as prescribed by the rules, between the heavier middleweight and the lighter featherweight.

Lacking in earnestness, ability, or profundity

Having less than average weight

Lacking in strength