/ˈmʌsti/ or /ˈmʌsti/ is an archaic or rare variant, /ˈmʌstɪ/ is more common for the word ‘mustie’ but ‘mustee’ is pronounced similarly, with stress on the first syllable

Definitions

1. noun

A person, especially an African American, who is considered to be of mixed race, often resulting from the union of a slave and a white person, especially during the time of slavery in the southern United States.

“The term ‘mustee’ was often used in historical documentation to refer to people of mixed ancestry.”