(after a verb or adjective) one who (is) ... / (after a noun) person involved in ... / -er / -ist / (used after a number or 後|后[hou4] or 前[qian2] to refer to sth mentioned previously) / (used after a term, to mark a pause before defining the term) / (old) (used at the end of a command) / (old) this
easy / amiable / to change / to exchange / prefix corresponding to the English adjective suffix "-able" or "-ible" / abbr. for 易經|易经[Yi4 jing1], the Book of Changes