salmon

From Middle English samoun, samon, saumon, from Anglo-Norman saumon, from Old French saumon, from Latin salmō, salmōn-. Widely displaced native Middle English lax, from Old English leax (whence modern dialectal lax). The unpronounced l was later inserted to make the word appear closer to its Latin root (compare words like debt, indict, receipt for the same spelling Latinizations).

The verb sense “ride a bicycle the wrong way down a one-way street” alludes to salmon swimming upstream against the flow of a river to spawn.