stiff upper lip

bite one's lip

To forcibly prevent oneself from speaking, especially in order to avoid saying something inappropriate or likely to cause a dispute.

button one's lip

To remain silent, especially in order to keep a secret or to avoid saying something inappropriate.

fat lip

A swelling on the lip, especially one resulting from a punch or other blow.

give lip

To speak to someone rudely or without respect.

lip service

Promising but empty talk; words without action or intention.

loose lip

The practice or characteristic of being overly talkative, especially with respect to inadvertently revealing information which is private or confidential.

shoot from the lip

To speak confidently and unhesitantly but without careful forethought or a reliable knowledge of important facts pertaining to the subject matter.

upper crust

The social elite, the highest social class.