ἐλλείπειν
From LSJ
ἔργοισι χρηστός, οὐ λόγοις ἔφυν μόνον → a friend in deeds, and not in words alone
Greek > English (Woodhouse Verbs Reversed)
(see also ἐλλείπω): fail, be deficient in, be deficient, be devoid of, be inferior to, be inferior, be wanting in, be wanting, fall short of, fall short, give out, leave out