im ‧ plau ‧ si ‧ ble /ɪmˈplɔːzəb ə l, ɪmˈplɔːzɪb ə l $ -ˈplɒː-/ BrE AmE adjective
difficult to believe and therefore unlikely to be true OPP plausible
implausible theory/idea/explanation etc
Margaret found his excuse somewhat implausible.
It’s not entirely implausible that a galaxy could be identical to our own.
—implausibly adverb
—implausibility /ɪmˌplɔːzəˈbɪləti, ɪmˌplɔːzɪˈbɪləti $ -ˌplɒː-/ noun [uncountable]