Translation

もっともらしい / あり得そうな / 信じられそうな

Meaning

Plausible means something seems reasonable or believable, but is not proven. The learner trap is translating it as possible. Possible only means it can happen; plausible means it sounds likely enough to take seriously.

Examples

• 彼の説明はもっともらしく聞こえましたが、証拠はありませんでした。
  His explanation sounded plausible, but there was no evidence.
• 隕石が原因という説は possible でも、この場合は plausible ではありません。
  A meteorite is possible, but in this case it is not plausible.