This charge does not necessarily depend on what you meant when you said it. It depends on how the other person perceived it and whether it placed them in fear.
The most effective way to avoid this charge is to watch your words when you are angry. What surprises most people is that the offense does not necessarily depend on what you meant when you said it. It depends heavily on how the other person perceived it.
Think of the scene in Twelve Angry Men where one juror yells at another that he will kill him. He does not mean it, and he is saying it out of anger. But if the other juror took it as a real threat and it placed him in fear, that is a terroristic threat allegation. Barrera Defense examines the context, the relationship, and what the state can actually prove about intent and perception.
Citation: Texas Penal Code §22.07
Degree and classification: Ranges from a Class B misdemeanor up to a third-degree felony depending on the target and purpose of the threat, such as a threat against a family member or public servant, or one intended to disrupt public services.
Statutory language: A person commits an offense if he threatens to commit any offense involving violence to any person or property with intent to place someone in fear, cause an emergency response, or disrupt a place or government function.