Consider the situation or storyline when deciding if something is implausible. The time travel plot in the movie was implausible given the realistic setting.
Pro Tip 2/3
Degree of Unlikeliness
'Implausible' doesn't mean impossible, but it suggests that something is very hard to believe. His explanation for the lost money was implausible but not impossible.
Pro Tip 3/3
Emotional Tone
Using 'implausible' can express skepticism or doubt about someone's statement or story. Her excuse for being late was so implausible that I couldn't help laughing.