Opera Singer Nellie Melba:
Czar and Julilus Ceasar…or for that matter, Ceasar salad and restauranteur Ceasar Cardini. Also, fettucine alfredo and restauranteur Alfredo di Lelio. I thought Margarita could be traced to a single person, but Wikipedia says otherwise.
The Kimura, a shoulder lock in BJJ, MMA and submission grappling (called gyaku ude-garami in Judo), was named after Judoka Masahiko Kimura by the Gracie clan, after he used it to break Helio Gracie’s arm.
Adidas and the company’s founder, Adolf “Adi” Dassler.
The Uzi submachine gun and its creator, Uziel “Uzi” Gal.
For that matter, July and August.
Mesmerize comes from Fraz Mesmer who was a German physician and astrologist
And of course, there’s Lord Douchebag. 
Also sousaphone, from JP Sousa of marching fame.
And the German Kaiser.
But interestingly, despite popular belief, *not * Caesarean section. The idea that Caesar was delivered by Caesarean section wouldn’t have worked anyway, because such a procedure in ancient Rome would invariably involve the death of the mother, and Caesar’s mother Aurelia lived to a ripe old age.
Anyway, a few more for the road:
Jacuzzi, from Royand/or Candido Jacuzzi.
Tantalize, from Tantalus.
Fata Morgana, from Morgan le Fay of Arthurian legend.
Jumbo, as in Jumbo Jet and other jumbo-sized things, from Jumbo the elephant.
Here’s a pretty obscure one: The Ameche for the telephone.
Named, not for an inventor, nor for someone who even inspired the invention, but for the actor who played the man who invented the telephone. When Don Ameche played Alexander Graham Bell in the 1939 film, The Story of Alexander Graham Bell, his name became synonymous with Bell’s.
Love the synchronicity of the post content and the username. 
Nachos are named after the guy who invented them – “nacho” is a nickname for “Ignacio.”
The OP asked for words named after people. The Mongols were a people, no?
And in that vein, the Australasian dessert Pavlova, named after the ballet star Anna Eponymous.
Makes my mouth water just thinking about it.
More specifically, the practice of creating outlandishly dressed effigies of Guy Fawkes, called ‘the guy,’ to burn on November 5; the name was applied to outlandishly dressed persons (“There was an Old Man with a poker, who painted his face with red ochre; When they said, ‘You’re a Guy!’ he made no reply, but knocked them all down with his poker”) and by extension to any fellow.
Hooligan was named after a particulary rowdy Irish family named Hoolihan.
Thank you for this one. Didn’t Dan Savage come up with the usage of his name for what it’s now used for (don’t want to get too TMI here)?
Yep. (Wiki article, perhaps TMI, with links to several Savage columns which employ decidedly more graphic language)
While that’s a possibility, there’s no evidence for it.
I know it doesn’t fit in with the OP, but I recently heard the term, Jack Welsh someone. It was used to describe firing someone who was possibly successful, but not in the top 90%, or higher.
SSG Schwartz