Cause trouble, especially a quarrel or fight, as in Stop bringing that up—do you want to start something? [Colloquial; early 1900s]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
How to use start something in a sentence
"You'd better keep those hands up," he went on quickly, as he saw the two rascals making a move as if to start something.The Outdoor Girls in the Saddle | Laura Lee Hope
"Oh, we'll start something, leave it to us," said Roly Poly.Pee-Wee Harris Adrift | Percy Keese Fitzhugh
It would be approximate, of course, but it would give us a start—something more definite than we have now.In Her Own Right | John Reed Scott
To tell the truth, I was spoiling for a fight and I half wished they would start something.Outwitting the Hun | Pat O'Brien
"You go awn and start something—and you'll wisht you hadn't," they heard him croak from the big gate, and chuckled over his wrath.Flying U Ranch | B. M. Bower