waster
Someone or something that wastes; someone who squanders or spends extravagantly.
An imperfection in the wick of a candle, causing it to waste.
A destroyer or plunderer.
obsolete
He also that is slothful in his work is brother to him that is a great waster.
An item that is spoiled during its manufacture.
Unless the cast was very hot indeed, the steel would refuse to ascend, and a great many wasters were caused thereby.
Where it comes from
From Middle English wastere, waister, wastar, wastour, equivalent to waste + -er. Compare Anglo-Norman wastur, Old French gastëor.
Adapted from the Wiktionary entry waster (CC BY-SA 4.0).