"Held a gun to one's head" is a phrase that denotes a threatening or coercive situation where someone forcefully forces another person to do something. It is a serious and violent act that can leave lasting traumatic effects. Some synonyms that can be used in place of this phrase are "held hostage," "held at gunpoint," "threatened with a weapon," or "confronted with a gun." These phrases can be used interchangeably to describe a situation where someone is being coerced or threatened by force. It is important to note that the use of such phrases should be taken seriously and not used in a joking or casual manner as it could trivialize the severity of the situation.