Back before Nixon, Dick was a perfectly allowable shortening of a first name for [edit: mostly] white American men called Richard. Dick Feynman, Dick van Dyke, Dick Sargent, even Dick Cheney. Only since the 70s / 80s has it become a perjorative among younger generations, perhaps because of the Liar in Chief.

The name Richard has significantly declined in popularity over the past century, and use of Dick as a nickname for it has declined even more.

Its use as a term of contempt predates Nixon by about 300 years: https://en.wikipedia.org/wiki/Dick_(slang)

Here's an interesting article on the history of shortening of Richard, Dick in particular [1].

[1] http://www.todayifoundout.com/index.php/2012/04/how-dick-cam...

only white?

I think this is a fair question. I think it was predominantly white men. Never heard of a black man named Richard being called Dick. I think they usually use Rick instead.

Richard ~= Rick == Dick

One exception was black comedian, author, and activist Dick Gregory.

I never got used to Richie Allen requesting that he be called Dick Allen https://www.baseball-reference.com/players/a/allendi01.shtml. I had no preference, but as a Phillies fan I had heard him referred to as Richie Allen a zillion times his first few years on the team so Dick Allen always clanged off my ears.

Dick is short for Richard

Good link, I didn't know that's what nicknames were called.

Nicknames seem to be a superset of hypocorisms, which are nicknames that are a shorter derivative or other modification of a person’s original name.

I imagine during a regular class he was Professor Feynman, during Physics X he was just Dick Feynman.