If you’ve been watching Street Outlaws and heard the term donk car only to be confused about what it means, you’re far from alone.
According to Wikipedia, a “donk car” is an endearing term that was given to the fifth-generation Chevrolet Impala and second-generation Chevrolet Caprice by enthusiasts. The name derives from the word “donkey,” as the Impala logo resembled a donkey to some owners. “Donkey” became “donk” as time went on, and thus “donk car” as a term was born.
Source: https://www.distractify.com/p/what-is-a-donk-car