means The capacity or willingness to accept, endure, or allow things you disagree with or find difficult—whether opinions, behaviors, pain, or a substance—without breaking down or pushing back.

from From Latin tolerare, "to bear, endure, put up with"—the same root that gives us "toleration" and is a cousin of "extol" and possibly the Greek tlenai ("to suffer, undergo"). It entered English in the 15th century, first meaning the literal endurance of pain or hardship; the sense of "putting up with other people's beliefs" came later, and the medical sense (a body "tolerating" a drug, needing more for the same effect) later still. At its heart the word never meant approval—only the strength to bear.