Green’s Dictionary of Slang

1. an excl. of pleasure or surprise.

1907		Marvel 2 Feb. 46: Hurroo! Whiroo! Skidoo!
1910		‘O. Henry’ ‘The Day Resurgent’ in Strictly Business (1915) 48: ‘Skiddoo!’ said Tim, closing a sophisticated eye.

2. a general term of abuse, scram! go away!

1904		L.A. Times 25 Dec. B2: ‘Skidoo for you, pal--get a live one.’.
1905		F. Hutchison Philosophy of Johnny the Gent 39: ‘Say,’ says I, ‘Skadoo! Back up!’.
1906		Guilelmensian (Williams Coll.) 253: Receipt for Skidoo pudding., Make a batter of 23 eggs and beat it.
1907		Leamington Spa Courier 24 May 3/5: I long wooed your daughter, but you said, ‘Skidoo’.
1908		Ren Shields & J Fred Helf ‘Whoop! Whoop!! Whoop!!!’ 🎵 Kiddo, just skidoo, / Fade away like the sun on a cloudy day.
1908		‘O. Henry’ ‘The Harbinger’ in Voice of the City (1915) 53: Skiddoo! Get your mind off of money.
1926		Wood & Goddard Dict. Amer. Sl. 49: skidoo. Beat it, depart, ‘23 for you’.
1933		J.T. Farrell Gas-House McGinty 36: The Old Man said skeedoo right there and then.
1934		H. Roth Call It Sleep (1977) 289: ‘Gwan!’ The older ones blustered. ‘Skidoo!’.
1940		Harrisburn Sun. Courier (PA) 15 Sept. 6/5: He opened the door and called, ‘Skidoo, you sons-of-guns.’ The owl skidooed.
1953		T. Williams Camino Real Block Twelve: The solar system is drifting towards the constellation of Hercules: Skiddoo!

3. (US) nonsense! rubbish! fig. use of ‘get away!’.

1905

F. Hutchison Philosophy of Johnny the Gent 49: ‘I've been an unpaid booster fer the distillery trust long enough.’ [...] ‘Aw, skadoo!’ interupted the Night Hawk Cabby. ‘I’d like to have a little bet down that I’ll be haulin’ you home an’ carryin’ you upstairs again before the week’s out’.