unfailing
Concise Oxford English Dictionary © 2008 Oxford University Press:
unfailing/ʌnˈfeɪlɪŋ/
▶adjective
- 1 without error.
- 2 reliable or constant.
– derivatives
unfailingly adverb,
unfailingness noun.
unfailingly adverb,
unfailingness noun.
'unfailing' also found in these Oxford entries:

