Are yams and sweet potatoes the same?
c.1500, "rough, stormy;" 1540s, "not manageable," from Latin intractabilis "not to be handled, unmanageable," from in- "not, opposite of" (see in- (1)) + tractabilis (see tractable). Related: Intractably.
intractable in·trac·ta·ble (ĭn-trāk'tə-bəl)adj.
Difficult to manage or govern; stubborn.
Difficult to alleviate, remedy, or cure.