This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

adj. Not to be named or identified: "We lived in dread of various unnameable calamities” ( Garrison Keillor).

adj. That cannot, or should not, be named

adj. too sacred to be uttered

"Odorants classified as unnameable were rated as significantly more difficult to name than odors classified as nameable."

sacred   

partial-birth    irremissible    unconfessed    terror-filled    unnamable    salt-laden    ungraspable    Bolshevik    world-old    deistic