makeweight

noun

1. something put in a scale to complete a required weight.
2. anything added to supply a lack.

noun

1. something put on a scale to make up a required weight
2. an unimportant person or thing added to make up a lack

n.also make-weight, 1690s, “small quantity of something added to make the total reach a certain weight,” from make (v.) + weight. MAKE WEIGHT. A small candle: a term applied to a little slender man. [“Dictionary of Buckish Slang, University Wit, and Pickpocket Eloquence,” London, 1811]