Green’s Dictionary of Slang

duchess v.

[note letter from Paul Kunino Lynch 12/9/00: Duchess is ‘widely understood here as meaning what happens when an Australian or other provincial goes to the UK, and British power figures try to sap the visitor’s will & judgment by overpowering them with experiences such as weekends in the luxurious homes of the mighty, duchesses and such. Presumably this used to work once upon a time, and it was at its peak during WWI. Verb both transitive & intransitive. I was duchessed, they duchessed or tried to duchess me. Stupid bastard went to London and let them duchess him [...] So the central meaning of the word is “treated by (generic) duchesses”, rather than like them’]

[1950s+] (Aus.) to treat in a patronizing manner, in the image of a stereotyped duchess; trad. attributed to the treatment by certain Britons of visiting Australians.