Plausibly means in a way that sounds believable. Argue plausibly.
Sounding right and being right are different things, which is the whole warning in the word. Something stated plausibly gets past people who would question the same claim stated badly.
1adverbplausiblyIn a way that sounds believable.
“He explained it plausibly and every word was invented.”
plausibly is a manner.
Latin
plausibilis — deserving applause, praiseworthy, acceptable, pleasing
English
plausible
English, today
plausibly
Built from
From plausible + -ly. plausible comes from Latin plausibilis (“deserving applause, praiseworthy, acceptable, pleasing”), from the participle stem of plaudere (“to applaud”).
Etymology from Wiktionary, CC BY-SA