Green’s Dictionary of Slang

1. (US) a fool, a synon. for shine n.² (3); a failure.

1901		‘Hugh McHugh’ Down the Line 93: Sybil was a polish for sure.
1902		Ade Forty Modern Fables 95: Still, the Hotel was not altogether a Polish.
1905		‘Hugh McHugh’ You Can Search Me 15: Say, John! I’m a polish, for fair!

2. effrontery, arrogance.

1900

Sporting Times 27 Jan. 2/2: It is true that some of the Newmarket trainers used to smile at the polish, or ‘side’ of the late James Jewitt.

3. (N.Z.) fellatio.

1982		G. Newbold Big Huey 252: polish (n) Act of fellatio upon a male.
1989		R.G. Barrett Boys from Binjiwunyawunya 194: I get the best blow jobs I’ve ever had in here [i.e. prison] [...] One of the screws [...] brings me in bottles of perfume [...] and I swap it with the drags for a polish.
1988		McGill Dict. of Kiwi Sl. 86/1: polish, a fellatio; eg ‘Whadya want, sailor, all the way or just a polish?’.
2000		R.G. Barrett Leaving Bondi (2013) [ebook] ‘What about blow jobs? [...] Is there any chance of finding a polish in here?’.
2003		McGill Reed Dict. of N.Z. Sl. [as cit. 1988].

4. an act of masturbation.

1994

Penguin Bk of Aus. Jokes 452: She gives the old chap a ‘polish’.