philippic

Philippic comes from Latin philippicus, from Ancient Greek philippikós, which described things belonging to Phílippos — a name built from phílos, "loving," and híppos, "horse."

The facts given trace only the word's roots in the name Phílippos, "lover of horses"; they don't describe how it came to mean a fierce denunciation, so that shift isn't something I can honestly fill in here.

It shares its second half with híppos, "horse" — the same root that shows up in English words like hippopotamus.