• (n.) A principle or mixture of principles derived from Euonymus atropurpureus, or spindle tree.
Eu·on'y·min noun (Medicine) A principle or mixture of principles derived from Euonymus atropurpureus , or spindle tree. 
Euonymin is an extract from the bark of the wahoo tree or spindle tree (Euonymus eruopaeus), and formerly used in medicine as a powerful stimulant to the liver, with a mild carthartic action on the intestine.