Secret and Unmentionable thing

Secret noun - Information shared only with another or with a select few.

Unmentionable thing and secret are semantically related In some cases you can use "Unmentionable thing" instead a noun "Secret".

Nearby Words: secretive, secrecy, secreted, secretly, secretary

Secret and unmentionable thing are semantically related in closely kept secret topic. You can use "Secret" instead a noun phrase "Unmentionable thing".