Unremittingly is the adverb of unremitting: it says that something goes on and on with no easing off at all. Two jobs, really. It can describe how an action is done — "she worked unremittingly for three years" means she kept at it without letting up. More often in writing it sits in front of an adjective and pushes it to the limit: unremittingly bleak, unremittingly grim, unremittingly cheerful, unremittingly hostile. In that use it means "in this way all the way through, never once otherwise". "An unremittingly bleak novel" is a book with not one hopeful page in it. That second use is where you will actually meet it — book reviews, film reviews, serious journalism. It is a long formal word and it sounds it; nobody says it over dinner. In speech you would say "non-stop", "the whole way through", "without a break". One small thing: because it is so heavy, using it about small matters sounds funny, and English writers do sometimes use it that way on purpose — "unremittingly polite" about someone whose politeness has become tiring.

不間斷地、毫不鬆懈地、從頭到尾都如此；如 unremittingly bleak（整部作品陰鬱到底，沒有一處喘息）。