A method used mostly by traders, to predict the future value of a coin/token. TA is based mostly on charts/graphs, that traders study and analyze in order to locate patterns that keep on repeating themselves ... these repeating patterns are usually followed by certain price movements that the traders try to make money from.
Technical analysis works the best in mature markets that are data driven and are prone to manipulation, panic and impulse behavior ... that's why some traders claim TA is not usable in the crypto space.