(slang, UK, Ireland, Commonwealth) A long time (especially a longer time than expected); ages
Haven’t seen him in yonks!
I’ve been a teacher for yonks–I should really try another career.
This egg is taking yonks to boil.
1968 August 27, Christopher Ward, “The Christopher Ward Page”, in Daily Mirror, London, page 7:
I rang singer Julie Driscoll […] She said: "I haven't heard from you for yonks[…]"
1975 January 28, Bill Stewart, “Comic Cuts”, in Evening Chronicle, number 30393, Newcastle, page 7:
Alas, the comics for that age group have nearly all picture stories today—and of course the ones for younger readers have been that way for yonks (sorry, years).
1982, Alan Bennett, “A Woman of No Importance”, in The Complete Talking Heads, Picador, published 2010, →ISBN, page 14: