Green’s Dictionary of Slang

(Aus./Irish) haughty, unfriendly.

1888		Mrs. H. Ward Robert Elsmere I 50: People generally like the other two much better. Catherine is so stand-off.
1904		G.B. Shaw John Bull’s Other Island IV ii: Well, we mustnt be stiff and stand-off, you know.
1918		K.F. Purdon Dinny on the Doorstep 238: You’re so horribly stand-off!
1922		A. Brown Old Crow 395: She had a direct address country folk liked. She was never ‘stand-off,’ ‘stuck-up’.