Is it ensure, insure, or assure?
mid-14c., from Old English gingifer, from Medieval Latin gingiber, from Latin zingiberi, from Greek zingiberis, from Prakrit (Middle Indic) singabera, from Sanskrit srngaveram, from srngam "horn" + vera- "body," so called from the shape of its root. But this may be Sanskrit folk etymology, and the word may be from an ancient Dravidian name that also produced the Malayalam name for the spice, inchi-ver, from inchi "root." Cf. gin (v.). The word apparently was readopted in Middle English from Old French gingibre (Modern French gingembre). Meaning "spirit, spunk, temper" is from 1843, American English. Ginger-ale recorded by 1822; ginger-snap as a type of cookie is from 1855, American English.
Energy; pep; pizzazz: the effervescent quality that used to be called ''ginger''
[1843+; fr the practice of putting ginger under a horse's tail to increase its mettle and showiness, noted by 1785]