Usually an employee is fired due to performance issues or misconduct.
However, gossiping can be considered misconduct, especially if it is disruptive to the workplace or damages the company's reputation. For example, if you are constantly spreading rumors about your coworkers or making false statements about the company, your employer may take action against you. Additionally, if you are using company time or resources to gossip, you may be considered to be in breach of your contract of employment and could be fired for this reason.
If you are concerned about being fired for gossiping, it is best to avoid doing it altogether. If you do find yourself in a situation where you are tempted to gossip, take a step back and think about the consequences before you speak.