cod

The word's roots are genuinely uncertain. One thread ties it to Old English cod or codd, meaning 'bag' or 'pouch,' from a Proto-Germanic word for something curved or arched. Another thread suggests the fish name may trace back through Latin gadus to Ancient Greek gádos.

The 'bag' sense gave the word a bloated, pouch-like feel that shows up across its Germanic relatives. Separately, and much later, 'cod' came to describe a person — attested from the late 1600s — though no one has ever pinned down why.

It shares its Germanic root with Scots cod (pillow), Swedish kudde (cushion), and Icelandic koddi (pillow) — all words that carry the same idea of something soft and swollen.