The psychic ability of clairsentience literally means clear sensing. Today the definition of clairsentience means the broad gift of being able to sense psychic information. Originally clairsentience was taken to mean the ability to sense smells projected by the spirit world, particularly familiar smells associated with passed loved ones.
In some ways a clairsentient is like a psychic sponge because they literally soak up everything around them in the environment. It is possible for them to sense people's health challenges also and this can be a very heavy burden. There is a great deal of the empath in most claisentients and they often need to take more steps in order to protect and ground themselves than other psychics.
It is an interesting gift without a doubt but can also be a little frustrating at times. "Knowing" or sensing an answer to a client's query does not always give as much information as might be helpful. As a somewhat silly example everyone knows that e=mc2. Knowing it and being able to understand why it is so are two completely different things.