Hearing, also known as the auditory sense, was the ability to sense sound with one's ears. Contrarily, deafness was the lack of a sense of hearing.
Elderly Humans could sometimes develop difficulty hearing, but with proper medical treatment, this was preventable. (TOS: "The Deadly Years", VOY: "Endgame")
In his poem "Ode to Spot", Data observed that Spot's auditory sense, along with his visual sense and his olfactory sense, contributed to his hunting skills and natural defenses. (TNG: "Schisms")
When Julian Bashir heard a sound within his comatose hallucination but Elim Garak could not, the latter speculated that Humans had better hearing than Cardassians. (DS9: "Distant Voices")
When three elderly Drayans noticed that Tuvok had pointed-ears, Elani asked him if they improved his hearing. He responded in the negative. (VOY: "Innocence")
Ferengi, partly due to their large ears, had a highly acute sense of hearing, making them exceptionally good at identifying sounds and voices. However, as a side effect, they could find loud sounds irritating, and certain frequencies could even be painful to them. (DS9: "Playing God", "Crossfire", "The Darkness and the Light", "Profit and Lace")