shortened form of excuse (v.), attested from late 15c.
Examples from the Web for scuse
"'Scuse us, but dat mast done goin' to tumble down," ventured a man.Blow The Man Down|Holman Day
"'Scuse me," Jake said, pulling a shawl more squarely around her shoulders and straightening her up.The Cromptons|Mary J. Holmes
Scuse me, Miss Ruth, but de chiluns done got cotched in de elevator!The Corner House Girls on a Houseboat|Grace Brooks Hill
Scuse me, Capn, but I happened to come in just then and couldnt help a–hearin ye.Fighting the Sea|Edward A. Rand
I'm going down to tell Amanda to 'scuse Reliance for just a few minutes.A Dear Little Girl's Thanksgiving Holidays|Amy E. Blanchard