Other forms: tortiously
In civil law, a tort is an act that brings harm to someone — one that infringes on the rights of others. The adjective tortious therefore describes something related to a tort.
Tortious interference occurs when you intentionally harm someone's business. If you claim that a restaurant uses rats in its stew, the owner can sue you for tortious interference. If, however, you can prove your suspicions are true, the restaurant will probably be closed by the health inspector. What's important is the intent of your actions — you've committed no tortious act if you tell the truth.