S(h)ellfish
the English word shellfish
derived from the English word fish
derived from the English word fisc
derived from the French word fisc
derived from the Latin word fiscus (money-bag, purse; imperial exchequer)
derived from the Proto-Germanic root *fiskaz
derived from the English word shell
derived from the Proto-Indo-European root *skel-
derived from the Proto-Germanic root *skaljo
the English word selfish
using the English suffix -ish
derived from the English word self
derived from the Proto-Germanic root *selba-