Tenable
Etymology
From French "tenable," from "tenir" ("to hold"), from Latin "tenēre" ("to hold, keep"). Its earliest English uses were military — a fort or position one could hold against attack. That literal defensibility carried straight over into arguments and opinions.
adjective · /TEN-uh-bul/
Able to be defended, held, or maintained against objection.
What it names
A position that survives scrutiny — not necessarily correct or persuasive, just capable of being held without falling apart.
Example
Once the new data came in, his original theory was simply no longer tenable.
Related idea
The opposite of spurious: a spurious claim is false or fake at its core, while a tenable one holds up even if it is later proven wrong.