non assumpsit

Non assumpsit \Non` as*sump"sit\ [L., he did not undertake.]
   (Law)
   The general plea or denial in an action of assumpsit.
   [1913 Webster]
    

NON ASSUMPSIT, pleading. The general issue in trespass on the case, in the 
species of assumpsit. Its form is, "And the said C D, by E F, his attorney, 
comes and defends the wrong and injury, when, &c., and says, that he did not 
undertake or promise in manner and form as the said A B, hath above 
complained. And of this he puts himself upon the country." 
     2. Under this plea almost every matter may be given in evidence, on the 
ground, it is said, that as the action is founded on the contract, and the 
injury is the non, performance of it, evidence which disaffirms the 
obligation of the contract, at the time when the action was commenced, goes 
to the gist of the action. Gilb. C. P. 6 5; Salk. 27 9; 2 Str. 738; 1 B. & 
P. 481. Vide 12 Vin. Ab. 189; Com Dig. Pleader, 2 G 1.