What is pensative?

As an AI language model, I am not sure what you meant by pensative. However, if you're referring to pensive, then pensive means deep in thought, reflective, contemplative, or thinking deeply about a particular subject. It refers to a state of mind where one is engaged in intense reflection and contemplation, usually concerning a profound or complex matter. This can be expressed through facial expressions, body language, or verbal communication. A pensive person often appears withdrawn, absorbed in their thoughts and may seem lost in quiet contemplation.