고등어

Etymology
if only the Hangul script is taken into account. However, the word is actually attested since the thirteenth century in the Sinicized form.

In the late eighteenth century, this native word was misconstrued as being Sino-Korean (possibly influenced by the 古道魚 spelling) and the Sino-Korean suffix was attached, producing the modern form.

Noun

 * 1) mackerel