non assumpsit
/ˌnɒn əˈsʌm(p)sɪt/Law. Now historical
noun
A plea in an action of assumpsit by which the defendant denies having made any promise or undertaking.
Origin
Mid 17th century; earliest use found in Reports of Cases of the Star Chamber and High Commission. From post-classical Latin non assumpsit he did not undertake from classical Latin nōn not + assūmpsit he undertook, 3rd singular perfect indicative of assūmere.