unrelenting

a.不屈不挠的，不松懈的

unquestioned, unquestioning, unquestioningly, unquiet, unquote, unravel, unread, unreadable, unreadiness, unreal, unrealistic, unreality, unreasonable, unreasonably, unreasoning, unrecognized, unreel, unregenerate, unregulated, unrelated, unrelentingly, unreliable, unremarkable, unremitting, unrepeatable, unrepentant, unrepresentative, unrequited, unreserved, unreservedly, unresolved, unresponsive, unrest, unrestrained, unripe, unrivalled (US unrivaled), unroll, unruffled, unruliness, unruly,