Niggerish vs Niggerism - What's the difference?

As an adjective niggerish

is like or characteristic of a nigger.

political support for black people.

(en adjective)

(derogatory, offensive, ethnic slur) Like or characteristic of a nigger.

* 1866 , The Atlantic Monthly :

So when I say that my Auntie's piety was not of the niggerish kind...

* 1886 , Michael Magaul & Eli Robinson McCall, No-history Versus No-war or The Great Tootle Rebellion Exposed , p. 261:

*:[T]hey should specially avoid the fanatics who

*1958 , "Talking About", Jet , Vol. 14, No. 3, p. 47:

*:She told him in her native Virginia mountain-area dialect: "That's what ah said. Ah don't like these niggerish places."

* 2002 , Loretta I Winters, Herman L DeBose, New faces in a changing America :

In a voice dripping with sarcasm, Bernhard related, "Mariah's been getting a little niggerish on us... she been seeing those rap stars..."

* niggery

(uncountable, dated, derogatory, offensive, ethnic slur) Political support for black people.

* 1976 , William Fletcher Thompson, The History of Wisconsin

Their black support confirmed the charge of "niggerism " and helped the Democrats turn the widespread Negrophobia to their account.

* 1988 , Philip M Seib, Who's in Charge?

The spot quoted a Klan official saying, "In Alabama, we hate niggerism , Catholicism, and Judaism."

(countable, dated, derogatory, offensive, ethnic slur) Something characteristic of niggers.

* 1970 , Claude McKay, Banjo

He loved their tricks of language, loved to pick up and feel and taste new words from their rich reservoir of niggerisms .

* 1975 , Daniel J Leab, From Sambo to Superspade: the Black experience in motion pictures

But as it was, not until the 1940s did the industry begin to depart significantly from the stereotypes with their "insulting niggerisms "...