WordNet: implacable

incapable of being placated; "an implacable enemy"

• also see merciless, unmerciful

• similar to grim, inexorable, relentless, stern, unappeasable, unforgiving, unrelenting

• similar to unmitigable

implacable

• (englanti) placable (antonym)
• (suomi) hellittämätön (synonyymi)