A benevolent spirit imagined as accompanying a person throughout his or her life and exerting a good influence, and often paired with an opposed malevolent spirit.
Origin
Early 17th century. From post-classical Latin bonus genius from classical Latin bonus good + genius.
Definition of bonus genius in US English:
bonus genius
nounˌbəʊnəs ˈdʒiːnɪəs
archaic, literary
A benevolent spirit imagined as accompanying a person throughout his or her life and exerting a good influence, and often paired with an opposed malevolent spirit.
Origin
Early 17th century. From post-classical Latin bonus genius from classical Latin bonus good + genius.