Meaning

noun intense feelings of suffering; acute mental or physical pain

noun a state of acute pain

origin14th century, via Old French and Latin from Ancient Greek ἀγωνία (agōnía, “emulation, competition, struggle”), from ἀγών (agṓn, “contest”). Specifically of the struggle that precedes death (mortal agony) from the 1540s. By surface analysis, agon + -y. The sense of "extreme pain" from c. 1600.

Etymology from Wiktionary, CC BY-SA 3.0