exception

a claim or excuse used within a legal defence, which was made with the intention of stopping a case in its tracks.  The ‘exception of non-numerate money’ (exceptio non numeratae pecuniae) was a claim that the money due to be repaid by a debtor had never been paid, or never properly paid in the first place. The exceptio rei judicatae ‘the exception of the thing judged’ was a claim that the case under consideration had already been tried by a different court.