dēsertĭo — Lewis & Short
dēsertĭo, ōnis, f.2. desero,
I a forsaking, deserting (rare; perh. not ante-Aug.).— Milit. t. t. (acc. to 2. desero, no. I. B.), desertion:
peccatum desertionis,Dig. 49, 16, 3, § 6; 5, § 2 al.