“The word mora means delay or default. In its technical sense it means a culpable delay in making or accepting performance…. The definition includes both mora debitoris and mora creditoris. In French law and other civil law systems mora debitoris seems (sometimes, if not always) to occur as a mean term between failure to perform a duty timeously and liability for breach….Mora usually attaches to a debtor, but it may also attach to a creditor who fails to accept performance duly tendered ….” R.W. Lee, An Introduction to Roman–Dutch Law 445 (4th ed. 1946).
“Mora. This was wrongful failure to discharge a legal obligation on demand made at a fitting time and place. It must be wilful: failure to appear, by mistake, or in a bona fide belief that there was no obligatio, or doubt about it, or by mishap, did not suffice to put a debtor in mora.” W.W. Buckland, A Manual of Roman Private Law 338 (2d ed. 1939).
mora (mor-[schwa]), n. [Law Latin] Hist. A moor; unprofitable ground.