(obsolete) The quality of deserving applause, praiseworthiness; something worthy of praise. / (now rare) The appearance of truth, especially when deceptive; speciousness.

Seemingly or apparently valid, likely, or acceptable; conceivably true or likely / Obtaining approbation; specifically pleasing; apparently right; specious.

(manner) In a plausible manner. / (modal) Probably; not falsifiably, based on available facts and general knowledge.

plural of plausibility

The state or quality of being plausible.

(politics, business, military, espionage) The organization of clandestine activity in such a way that knowledge of its existence may be denied by those in authority.