Final answer:
A frowning is an example of a negative informal sanction. Informal sanctions are not officially enforced but play a role in social control by discouraging deviant behaviors.
Step-by-step explanation:
An example of a negative informal sanction is frowning.
Informal sanctions are reactions or consequences that occur in face-to-face social interactions. They are not officially enforced, but they play a role in social control by discouraging behaviors that violate social norms.
When someone frowns at your action, it signifies their disapproval, and it can serve as a punishment for deviating from social expectations.