From apo and algeo (to smart); to grieve out, i.e. Become apathetic -- be past feeling.
see GREEK apo
a. to bear troubles, with greater equanimity, cease to feel pain at: Thucydides 2, 61 etc.
b. to become callous, insensible to pain, apathetic: so those who have become insensible to truth and honor and shame are called ἀπηλγηκότες (A. V. past feeling) in Ephesians 4:19. (Polybius 1, 35, 5 ἀπηλγηκυιας ψυχάς dispirited and useless for war (cf. Polybius 16, 12, 7).)