Is "bad luck" recognized in Islam, how can one get rid of it, and what is the ruling on someone who describes people as such?

This action stems from pessimism and omens, which are forbidden in Islam. It is not permissible for anyone to be pessimistic about another person, because whatever happens is by divine decree and destiny. Pessimism is ill-faith in Allah, while optimism is good faith in Him. Allah has clarified in Surat Ya-Sin the stance of the people of the town who took the messengers as bad omens. The messengers responded to them by saying that their ill omens and deeds were with them. It is not permissible for your brother to have ill-faith in Allah and be pessimistic about you or others, nor to judge your future success or failure; for that is part of the knowledge of the unseen, which only Allah knows. Therefore, he must fear Allah, repent to Him, and restrain his tongue from speaking ill of Muslims.