(Ἀγώνιος), a surname or epithet of several gods. Aeschylus (Aesch. Ag. 513) and Sophocles (Soph. Trach. 26) use it of Apollo and Zeus, and apparently in the sense of helpers in struggles and contests. (Comp. Eustath. ad Il. p. 1335.) But Agonius is more especially used as a surname of Hermes, who presides over all kinds of solemn contests. (Ἀγώνες, Paus. 5.14.7; Pind. O. 6.133, with the Schol.)
[L.S]A Dictionary of Greek and Roman biography and mythology
Smith, William
A Dictionary of Greek and Roman biography and mythology. William Smith, LLD, ed. 1890