Hostility was a negative attitude towards others that could include ill will, enmity, and denigration.
Several of J'Vini's criminal charges included hostile intent. (DIS: "Choose to Live")
In a situation where four strangers were abducted and confined to a small room, they might become suspicious of each other. There would be false accusations against one or more of them being in collaboration with the abductors, creating hostility between the strangers which could lead to violence and ending with their suspicions destroying them. (TNG: "Allegiance")
In 2373, Tom Paris asked B'Elanna Torres why she so often had to get hostile after an angry outburst from her. She protested that she was not. Later, she brought up the issue to Harry Kim, asking him if he thought she was hostile. He replied that he would not describe her that way, but she pressed the issue, stating that she had a temper, but that it did not mean she was always hostile. She continued that she was forthright and spoke her mind, but that this was different from being hostile. She then asked Kim to agree that anyone describing her that way would be way off the mark and he meekly agreed, but she questioned why he looked like he was afraid for his life. (VOY: "Displaced")