from
Bouvier's Law Dictionary, Revised 6th Ed (1856)
CASUAL EJECTOR, practice, ejectment. A person, supposed to come upon land
casually, (although usually by previous agreement,) who turns out the lessee
of the person claiming the possession against the actual tenant or occupier
of the land. 3 Bl. Com. 201, 202.
2. Originally, in order to try the right by ejectment, Several things
were necessary to be made out before the court first, a title to the land,
in question, upon which the owner was to make a formal entry; and being so
in possession he executed a lease to some third person or lessee, leaving
him in possession then the prior tenant or some other person, called the
casual ejector, either by accident or by agreement beforehand, came upon the
land and turned him out, and for this ouster or turning out, the action was
brought. But these formalities are now dispensed with, and the trial relates
merely to the title, the defendant being bound to acknowledge the lease,
entry, and ouster. 3 Bl. Com. 202;.Dane's Ab. Index, h.t.