Definition of "cinch"

He found Andy morosely replacing some broken strands in his cinch, and he went straight at the mooted question.

1915, B. M. Bower, The Flying U's Last Stand

We thought we had a cinch on getting out by way of this cord and so we followed that.

1913, Major Archibald Lee Fletcher, Boy Scouts in the Coal Caverns

The job was a snap. I travelled the country averaging a thousand miles a week and, since the previous incumbent had been a lazy bugger, managed to treble the business. It was a cinch.

2003, Clive Selwood, All the Moves (but None of the Licks), page 33

As a matter of fact, from the look of Elmer's shoulder, it wasn't a cinch that he would ever pitch again.

1916 March 11, Charles E. Van Loan, “His Folks”, in Saturday Evening Post‎

You've got the cinch on him. You could send him to quod, and I'd send him there as quick as lightning. I'd hang him, if I could, for what he done to Lil Sarnia.

1916, Gilbert Parker, The World For Sale

[Ostriches] also lack the tiny hooks, or barbicels, that cinch feathers together in most other birds.

2020 August 4, Richard Conniff, “They may look goofy, but ostriches are nobody’s fool”, in National Geographic Magazine‎