Green’s Dictionary of Slang

(US) a Jesuit.

1946		J.F. Powers ‘Prince of Darkness’ in Accent (Winter) 85: ‘Hopkins has some good things.’ ‘Good—yes, if you like jabberwocky and jebbies! I don’t care for either’.
1947		H. Sylvester Moon Gaffney 60: The Jebbies will give you space in their basement on Eighty-fourth Street.
1965		(con. WWI) D.V. Gallery Eight Bells 27: The Latin, Greek, and ancient history that the Jesuits taught were of no use on those exams. The Jebbies didn’t bear down too hard on Math, and the Navy did [HDAS].
1977		(con. 1949) J.G. Dunne True Confessions (1979) 43: The jebbies wanted the Cardinal’s approval on that new dormitory.