Plausible
Etymology
From Latin "plausibilis" (deserving applause), from "plaudere" (to applaud, clap). It once literally meant applause-worthy; the drift to "merely believable-sounding" leaves a faint warning inside the word — the plausible is what an audience will accept, not necessarily what is real.
adjective · /PLAW-zih-bul/
Seeming reasonable or believable on its face, whether or not it is true.
What it names
A handle for claims that pass the sniff test — a signal about surface credibility, deliberately silent on whether the thing is actually so.
Example
His excuse was plausible enough that no one checked — which was the whole point.
Related idea
Distinguish it from probable: probable claims something is likely to be true; plausible claims only that it could be true without obvious objection. "Plausible deniability" trades on exactly this gap — a story that holds up, truth unexamined.