What is the root word of abandon?

The root word of "abandon" is "abandon" itself. It comes from the Old French word "abandonner" which means "to give up, to forsake".

While there is no shorter root word within the English language, "abandon" has roots in Latin: "ab" (away from) and "bandum" (a band or group).

So, while "abandon" is its own root, its origins can be traced back to those Latin words.