Dictionary of Medieval Names
from European Sources

Sinister m. Latin sinister 'left-handed; improper; inauspicious'.

France
Middle French
1421 Senestre favier 1325
Cite as: S.L. Uckelman. "Sinister". In S.L. Uckelman, ed. The Dictionary of Medieval Names from European Sources, Edition 2016, no. 4. http://dmnes.org/2016/4/name/Sinister.