Is it permissible for a young man, intelligent and academically advanced, who is compelled to interact with his non-hijabi female colleagues in university and at home, to joke with them?

It is impermissible for a Muslim man to be in seclusion with a non-mahram woman, or to prolong conversation with her. It is only permissible to speak with her to the extent of need, with politeness, modesty, and without softness of speech. It is disliked to initiate greetings with her, even when offering condolences. It is not permissible to sit with women, as it is forbidden and a gateway to temptation. Your visits to their homes do not constitute a necessity that permits such an act. It is not permissible for a non-mahram man to teach the Qur'an to a non-mahram woman if it leads to seclusion or temptation. However, if there is a need to teach her without seclusion, and the knowledge is necessary, then it is permissible under conditions: safety from temptation, absence of seclusion with the presence of someone who negates seclusion, and the woman being veiled and modest.