Is it permissible for a 21-year-old woman to play and converse with her male cousin of the same age while she is wearing the niqab and without being in seclusion?

If there is no proven legitimate suckling relationship between a woman and the children of her maternal uncles and aunts, and her paternal uncles and aunts, then they are non-mahram to her, and she must treat them on that basis. Thus, it is not permissible for her to play with her non-mahram cousin (son of her maternal aunt) or speak with him without need, even if she wears a niqab, because he is like any other non-mahram man. Scholars have stipulated the prohibition of speaking with a young non-mahram woman without need because it is a source of temptation, unless there is a need, along with adherence to Islamic guidelines.