Definition of "greaser"

The pole was greased and men tried to walk out to the end of it and dislodge the crate. The pole was supple, the crate swayed as each man crept out clinging desperately and finally fell off into the sea. […] People roared with laughter and greasers applied fresh grease for the next person's try.

1942, Emily Carr, “Regatta”, in The Book of Small

... incidentally, our correspondent tells of a West Indian who applied for a job at Kings Cross as motion greaser - but with no idea of what he would have to grease and why. Invited to find out and return within a month, he did, and nowadays the Kings Cross engines are as efficiently greased as any on B.R.

1961 March, “Talking of trains”, in Trains Illustrated, page 131

By such standards, the Greasers are pretty minor stuff. Basically, they're just the 1970 version of that time-honored English figure, the Leather Boy. During the fifties, he was known as the Teddy Boy; in the early sixties, he became the Rocker; and now, after a couple of earlier attempts at revival, he's back yet again, the Greaser.

1970 March 29, Nik Cohn, “England's New Teen Style Is Violence”, in The New York Times‎

A pair of Greasers were ahead of me, but I could see only their outlines, and they didn't seem to interfere any with the scenery.

1907, Stewart Edward White, chapter 11, in Arizona Nights‎