"gild" and "guilt"
Wordplay
Act 2,
Scene 2
Lines 52-56a
Lady Macbeth
To gild means to cover something with a thin layer of gold which is called the gilt. So, according to this metaphor, Duncan’s blood will be their gilt as well as their guilt. In addition, the gold found in medieval times often contained impurities that gave it a reddish color—like blood.