"Taj" refers to a type of crown or brimless hat that's used in the Middle East and India. The famous "Taj Mahal" is an Indian temple whose name means "crown palace." "Swaraj" indicates the self-government of India at the times of its struggle for independence from the British Empire.
Very few words end with J in the English language. Those that do have been borrowed from foreign languages such as Arabic or from Indian dialects to indicate concepts or ideas that don't have an equivalent English term. Terms such as "taj," "swaraj" or "hadj" are present in most dictionaries and are considered valid options when playing Scrabble.