from
Bouvier's Law Dictionary, Revised 6th Ed (1856)
PRECLUDI NON, pleading. A technical allegation contained in a replication
which denies or confesses and avoids the plea. It is usually in the
following form; "And the said A B, as to the plea of the said C D, by him
secondly above pleaded, says, that he the said A B, by reason of any thing
by the said C D, in that plea alleged, ought not to be barred from having
and maintaining his aforesaid action thereof against the said C D, because
he says that," &c. 2 Wils. 42; 1 Chit. Pl. 573.