per impossibile
/ˌpəːr ɪmpɒˈsɪbɪleɪ/originally Logic
adverb
As is impossible.
- Chiefly used parenthetically to qualify a proposition which can never be true..
Origin
Mid 19th century; earliest use found in Augustus De Morgan (1806–1871), mathematician and historian. From classical Latin per impossibile by impossibility (probably 2nd cent. a.d.: see note) from per + impossibile, use as noun of neuter of impossibilis.