EXAMPLES FROM THE WEB FOR CHUG
And chug, chug, he was off leaving only a trail of dirty smoke behind him.
I got telegrams from Laramie and the Chug, both, just before we left Russell.
To this "Chug" responded that he wished he wouldn't leave the office.
I had a feeling that every chug of the motor was carrying him further and further out of my life.
The third went true, striking with a chug and packing the crack.
She could hear its chug as it climbed the hill half a mile off.
Then came a chug, followed by a splutter, and the motor got into action.
The building shook and shivered with every chug of the machinery.
But the unbraced feet and the chug of the ball were too much for his balance.
There was a whir and chug of an arrested car on the drive under the window.
1866, echoic of a working steam engine. As a verb, from 1884. Related: Chugged; chugging. Drinking sense attested by 1940s (chug-a-lug), probably imitative of the sound of swallowing.