grātŭlātōrĭus — Lewis & Short
grātŭlātōrĭus, a, um, adj.gratulor,
I congratulatory (post-class.):
epistola, Capitol. Max. et Balb. 17: cena,Jul. Val. Rer. Gest. Alex. 3, 34 al.—Adv.: grātŭ-lātōrĭē, in a congratulatory manner:
mirari,Aug. Conf. 8, 6.