Definition of "bish"

Kate McKinnon, playing Hillary Rodham Clinton, on a series of cue cards: I know you're an elector / And on December 19th... / You're supposed to vote for Donald Trump / But bish... / ...He cray

2016 December 17, Saturday Night Live (comedy sketch), National Broadcasting Company

What on earth was the matter with him? He never made bishes like this during PT!

1951, Anthony Buckeridge, Jennings Follows a Clue, page 41

"You — you don't mean you've made a bish of it?" [said Darbishire]

1952, Anthony Buckeridge, Jennings and Darbishire, London, Glasgow: Collins, page 64

'It's all right, bish,' said Augustine.'All—all right?' faltered the bishop.

1927, P. G. Wodehouse, “The Bishop's Move”, in Meet Mr Mulliner

BALDRICK: My Lord, the Bishop of Bath and Wells.BISHOP: (enters) The time has come, Blackadder!EDMUND: Oh, hello, Bish.

1986, Blackadder TV series, Money (series 2 episode 4)

'The Bishop of Bangor called.' My father and the bish were pals. 'He has received a strange request from the security service.'

2017, Rhodri Jeffreys-Jones, We Know All about You, page 1