Question

tinnitus means :
a silvery malleable metallic element that resists corrosion
a bacterial infection causing rigidity and muscle spasms
a ringing or booming sensation in one or both ears
a reference book containing a classified list of synonyms

Explanation:

Tinnitus is a medical condition characterized by a ringing, buzzing, hissing, or booming sound in one or both ears when no external sound is present. It is not related to a metallic element, a bacterial - infection symptom, or a reference book.

Answer:

a ringing or booming sensation in one or both ears