meaning - What does ゴン part in イノゴン mean?

I know what イノ is from イノシシ (wild boar), and I thought maybe ゴン is onomatopoeia for slam sound. Am I right or it's something else?

Answer

I would not necessarily call it an onomatopoeia. It should have more to do with what Japanese syllables sound strong and therefore suitable for monster names for the native speakers.

Those syllables are fairly widely believed to be ガギグゲゴ. There is even a book entitled 「怪獣{かいじゅう}の名{な}はなぜガギグゲゴなのか」.

https://www.shinchosha.co.jp/book/610078/#&gid=null&pid=1

「ゴン」 is a common ending among monster names without a clear meaning. I have no idea how that would sound to the speakers of your language, but it just sounds very monster-like to us Japanese-speakers after having grown up hearing and uttering so many monster names ending in 「ゴン」.

Back in college, a linguistics professor told us that 「ゴン」 probably came from 「ドラゴン」, which is indeed a very strong imaginary "monster".

「ゴジラ」 is no exception, either. Unlike what the "English" spelling might suggest, it has nothing to do with "god". That is said to be a combination of the strong-sounding 「ゴ」 from 「ゴリラ」 and the 「ジラ」 from 「クジラ」 ("whale"). Big and strong is the name of the game.

We even used to call the scary, demanding and monster-like mothers ママゴン.

Finally, one day back in my 4th- or 5th-grade, the entire classroom burst into laughter when our teacher uttered the U.S. state name 「オレゴン」.