Rule reminder
Both 'udire' and 'sentire' mean 'to hear' acoustically, but 'udire' is literary, formal, or archaic. 'Udire' is used in written narratives, poetry, legal language, and high-register contexts. Both take a bare infinitive for direct auditory perception. In everyday speech, 'sentire' is always preferred.
In a literary narrative: 'Il cavaliere _____ le grida dei nemici in lontananza.'