Alienate a friend; alienate potential supporters by taking extreme positions.
An example of alienate is when a family member has been abusing drugs, and their behavior has caused the rest of the family to no longer be able to tolerate having them around.
An example of alienate is when someone tells all your friends that you lied to them and your friends no longer speak to you.
The numbing labor tended to alienate workers.
His behavior alienated his friends.