Klesha is a Sanskrit word that the YogaSutra (an ancient text defining yoga) presents as a cause of suffering. Five of them are enumerated: misperception, egoism, attachment, aversion, and a fear-based clinging to the things of this life. They are often illustrated as a tree, with misperception as the trunk and the others as branches.
The kleshas show up often in my 1:1 sessions with clients, particularly attachment and aversion. Most of us have subconscious patterns of these, and discovering and shifting away from them can make a huge difference in reaching the next step on your path. (If this lands for you, feel free to schedule a 1:1 with me.)