Hush-hush and Tongue tie

Hush-hush adjective - Not known or meant to be known by the general populace.

Tongue tie and hush-hush are semantically related In some cases you can replace phrase "Tongue tie" with "Hush-hush", this phrases are similar.

Tongue tie noun - A congenital anomaly in which the mucous membrane under the tongue is too short limiting the mobility of the tongue.

Hush-hush and tongue tie are semantically related in silence topic. Sometimes you can use "Hush-hush" instead a verb phrase "Tongue tie", if it concerns topics such as make or be quiet.