The word 'wasabi' is a direct borrowing from Japanese, entering English in the late 19th to early 20th century alongside the growing international popularity of Japanese cuisine. In Japanese, 'wasabi' (山葵 or ワサビ) refers specifically to the plant Eutrema japonicum, a member of the Brassicaceae family related to horseradish and mustard. The term itself is of ancient Japanese origin, with no clear further etymology to Proto-Indo-European roots. The logic of its meaning is straightforward: the English word retains the exact referent of the Japanese original, denoting the pungent green root and the condiment paste made from it, which has become a staple flavoring in global sushi culture.

This is a direct loanword from Japanese. It is not segmented into meaningful morphemes within the English spelling system.