adverb
sincerely; earnestly; wholeheartedly
Used to emphasize a heartfelt request, warning, or expression of concern. Often appears in polite requests or when urging someone to take care.
くれぐれもお体に気をつけてください。
Please take good care of yourself.
くれぐれも無理をなさらないように。
Please don't overdo it, I sincerely mean it.
adverb
repeatedly; over and over; again and again
Rare, somewhat archaic use meaning 'repeatedly' or 'over and over'. In modern Japanese, the first sense (sincere request) is overwhelmingly more common.
昔の手紙では「くれぐれも申し上げます」と繰り返しの意味で使われることがあった。
In old letters, くれぐれも was sometimes used to mean 'repeatedly' as in 'I say again and again'.