We don't have synonyms for tinnitis yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are tinnitus, tinnitic and tenonitis.
(n) :
Misspelling of tinnitus. [(otolaryngology, pathology) The experience of auditory sensations, such as a ringing or pulsating sound, occurring in the absence of any external stimulus.]
(n) :
Misspelling of tinnitus. [(otolaryngology, pathology) The experience of auditory sensations, such as a ringing or pulsating sound, occurring in the absence of any external stimulus.]