Synonyms of the word 
UNHEARD → INAUDIBLE - UNHEARABLE
unheard
- adj. Not heard.
- adj. Not listened to.
- adj. Not known to fame; not illustrious or celebrated; obscure.
inaudible
- adj. Unable to be heard or not loud enough to be heard.
unhearable
- adj. That cannot be heard.
If you are interested in words, visit the following sites :
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- 1word.ws/unheard to play with words, suffixs, prefixs, etc.