Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Ăgōnālis, e, adj., pertaining to the Agonalia (cf. preced. art.): dies Agonales, per quos rex in regiā arietem immolat; dicti ab Agone (the leader, the chief), eo quod interrogatur a principe civitatis et princeps gregis immolatur, Varr. L. L. 6, § 12 Müll.: Janus Agonali luce piandus erit, Ov. F. 1, 318.