Relentless
来自Big Physics
wiktionary
relent + -less
etymonline
relentless (adj.)
"incapable of relenting, unmoved by pity, unpitying, insensible to the distress of others," 1590s, from relent + -less. Related: Relentlessly; relentlessness. Relenting is from 1590s as a present-participle adjective, "inclined to relent; too easily moved." For a noun for the group, relentment "act or state of relenting" (1620s) has been tried.
