Calumniæ Jusjurandum
Black's Law Dictionary · Henry Campbell Black, M.A. · 1910
Black's Law Dictionary
The oath of calumny. An oath imposed upon the parties to a suit that they did not sue or defend with the intention of calumniating, (calumniandi animo,) i. e., with a malicious design, but from a firm belief that they had a good cause.
Inst. 4, 16.