adjective [usu ADJ n] If you describe someone's good qualities or behaviour as unfailing, you mean that they never change. ⇒ He had the unfailing care and support of Erica, his wife. ⇒ ...a man of unfailing courtesy and kindness. ⇒ He continued to appear in the office with unfailing regularity thereafter. unfailingly
adverb [usu ADV adj, oft ADV with v] ⇒ He was unfailingly polite to customers. ⇒ Foreigners unfailingly fall in love with the place.
COBUILD Advanced English Dictionary. Copyright © Harper Collins Publishers