I thought her explanation was perfectly/entirely/completely 'plausible'. [=I believed her explanation]
a 'plausible' [='possible'] conclusion
a 'plausible' excuse
(..) to restore investor confidence. That is the Osborn way. Whoever's inconvenient around here, just get rid of it, right? Much of that scrutiny may fall on you now. - We felt that plausible deniability was your best option... - Sure, sure, I get it. Twenty-year-old kid. billion dollar company. (..)2014 The Amazing Spider-Man 2