Dictionary.com
definitions

mustee

[muh-stee, muhs-tee]
noun
  1. the offspring of a white person and a quadroon; octoroon.
  2. a half-breed.

Origin of mustee

First recorded in 1690–1700; short variant of mestizo
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for mustee

mustee

mestee (mɛˈstiː)

noun
  1. the offspring of a White person and a quadroon
  2. any person of mixed ancestry

Word Origin for mustee

C17: shortened from mestizo
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for mustee
n.

"octoroon, offspring of a white and a quadroon," also "half-caste," 1690s, a corruption of Spanish mestizo (q.v.).

Online Etymology Dictionary, © 2010 Douglas Harper