Definition of "git"

Although I'm so tired, I'll have another cigarette / And curse Sir Walter Raleigh, he was such a stupid git

1968, “I'm So Tired”, in John Lennon (lyrics), The Beatles, performed by the Beatles

Bit of a flash git, don't you think?

1990, House of Cards, season 1, episode 1

Eventually God gives the donkey a voice and it says, "why're you beating me you great stupid git? It's the angel with the sword that you gotta be careful of," or words to that effect.

2007, Greg Weston, The Man Upstairs, page 124

Parkinson: You made films before, but the part that really made your name was Zulu, wasn't it […] and there of course—against type—you played the toff, you played the officer.Caine: I played the officer, yeah, and everybody thought I was like that. Everyone was so shocked when they met me, this like Cockney guy had played this toffee-nosed git.

2000 December 18, BBC and Bafta Tribute to Michael Caine, 16:43-17:05

I'm not being a miserable old git here. I like a laugh as much as anyone, [...].

2020 December 16, Christian Wolmar, “Coverage of little-used stations does the railway no favours”, in Rail, page 45