Clairsentience is the ability to sense energies and things that are not visible to the naked eye.
Meg points out that all of the leviathans on Earth were inside Castiel, meaning that he can spot the real Dick Roman after he had a group of duplicates planted throughout SucroCorp headquarters as a cautionary measure. This proves to be key to identifying and killing Dick Roman.
After becoming a prophet of the Lord, Donatello Redfield gains the ability to sense the energies of both God / Chuck and the Darkness / Amara. He uses this ability to track down Amara's location, in order to rescue Lucifer.
Donatello reveals to the Winchesters that he found their motel room due to sensing the intense energy coming from Jack. Thinking it was God, he followed it to Wyoming, telling Sam and Dean he was drawn to it. He goes on to tell Jack that his energy is nothing like his father, Lucifer's, telling him it is, "Not dark, not toxic."
Missouri is able to read the energies in Dede's shop and recognize that a wraith came in pretending to be a customer and fed off her brain. She also receives two visions -- that her son James Turner and granddaughter Patience are in danger -- as well as her own death at the hands of the same wraith.
Castiel affirms that he can't accompany Sam, Mary, and Bobby to track Michael as he fears Michael would sense his angelic presence.
Michael reminds Castiel that he can sense his presence after he enters the Hitomi Plaza. After finding him, Michael goes on to severely beat Castiel into a bloody pulp.