Remember that you are here to earn a living and make a better future for you and your family. Therefore, you should try to work as hard as possible. Your focus should entirely remain on your work and nothing else. If you are working with full potential you will not find time for these things.
If your colleagues repeatedly try to involve you in their gossip gang, you should clearly tell them that you have no interest in gossips and your ultimate priority is your work. Eventually, if you do not pay attention to them, the gossips in your office will come to an end.
Tell the person gossiping to go and talk to the concerned person. Tell him that doing so would clear the confusion and he will be able to know the person well about whom he is gossiping around.
If the gossiper keeps spreading rumours about the subject, you should praise the concerned person and tell positive traits as this will contribute a great deal in putting end to the gossip.
While talking about the person who is being discussed, be wise and clear about the choice of words. Make sure none of your words can be used negatively in any way.