From Longman Dictionary of Contemporary Englishundyingun‧dy‧ing /ʌnˈdaɪ-ɪŋ/ adjective [only before noun] LONG TIMEcontinuing for everundying love/devotion/support etc They declared their undying love for each other.
Examples from the Corpus
undying• I have a huge amount of respect for him personally, and undying admiration for Greenpeace.• His only saving grace is his undying belief in the melodramatic.• The atmosphere did not encourage reasonableness and undying camaraderie.• Trading on the name and our undying devotion, Carlton have revived Crossroads.• One reader's St Valentine's Day post brought an interesting offer, but not of undying love and devotion.• Once in the barn, Stewart felt obliged to follow through on the expedition by dramatically expressing undying love for Susan Mary.• undying love• He also has my undying respect and jealousy for having been fortunate enough to have been born and raised in Tucson.undying love/devotion/support etc• She and I swore undying love.• One reader's St Valentine's Day post brought an interesting offer, but not of undying love and devotion.• Trading on the name and our undying devotion, Carlton have revived Crossroads.• Once in the barn, Stewart felt obliged to follow through on the expedition by dramatically expressing undying love for Susan Mary.• Labour seemed happiest when proclaiming its undying support for the National Health Service and the state education system of the post-Beveridge era.• The promises of undying love, of daily thoughts.• There had been no expression of undying love on the angular face she had come to love.• He kept apologising to Nellie and swearing undying devotion to her. 