im ‧ plac ‧ a ‧ ble /ɪmˈplækəb ə l/ BrE AmE adjective
[ Date: 1400-1500 ; Language: Latin ; Origin: implacabilis , from placabilis 'easily made calm' ]
very determined to continue opposing someone or something:
implacable enemies
The government faces implacable opposition on the issue of nuclear waste.
—implacably adverb :
He remained implacably opposed to Stalin’s regime.
—implacability /ɪmˌplækəˈbɪləti, ɪmˌplækəˈbɪlɪti/ noun [uncountable]