ipso facto: \ˈip-(ˌ)sō-ˈfak-(ˌ)tō\

by the very fact

As he is already married this marriage would be void ipso facto.


Sine qua non \ˌsi-ni-ˌkwä-ˈnän, -ˈnōn also ˌsē-; also ˌsī-ni-ˌkwā-ˈnän\

the most essential, necessity

Reliability is a Sine qua non for a job