Assalamu alaykum,if a muslim is listening to another person for example a kafir and he makes statements or expresses opinions which are contrary to islamic teachings and the muslims is smiling and nodding and making sounds like "mhm“ . Is this regarded as acceptance or approval of kufr which is kufr itself? Does this muslim commit kufr?Jazakumullahu khayran

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

This question undoubtedly stems from whispers. Whispers in general, and especially in this field, are a great door to evil.

Hence, our advice to you is to repel these whispers, ignore them and not pay any attention to them.

What you mentioned is not evidence of approval of Kufr; therefore, it is not Kufr.

A person may smile at such words with mockery and ridicule, or for some other reasons.

Hence, you must repel these whispers, ignore them and not pay any attention to them, because giving in to them will lead you to a great evil.

Allah knows best.