Are negative traits such as "malice" and "baseness" innate or acquired? Is one sinful for describing his brother with them? And what should a Muslim do if he is labeled with them and it affects him psychologically?

A Muslim must guard his tongue and beware of its slips, as Allah Almighty says: "Not a word does he utter but there is a watcher by him ready (to note it down)," and the Prophet, peace and blessings be upon him, said: "Indeed, a servant may utter a word, without realizing its implications, that causes him to fall into the Hellfire further than the distance between the East and the West." It is not permissible for a Muslim to accuse his brother of malice and meanness, for the Prophet, peace and blessings be upon him, said: "The whole of a Muslim is sacred to another Muslim." A Muslim is born with an innate disposition (fitra), and acquires good or bad manners through learning and environment. He must repel evil with good, as Allah Almighty says: "And not equal are the good deed and the bad. Repel [evil] with that which is better, and thereupon the one between whom and you was enmity [will become] as though he was a devoted friend," and he should rid himself of evil whispers by connecting with Allah, keeping company with righteous people, and seeking refuge from Satan.