subs. phr. (common).A sovereign; 20s.: also a crown piece; 5s. Hence TO SMASH (= change) or BLUE A THICK-UN.
1862. The Cornhill Magazine, vi. Nov., 648. If you like, Jerry, I will send a few THICKUNS to bring you and your tamtart up to Start.
1871. G. D. ATKIN, House Scraps, 111. Have you sufficient confidence in me to lend me a sovereign? Oh! yes, Ive the confidence, but I havent the THICK-UN.
1886. PERCY CLARKE, The New Chum in Australia, 143. If he has a drought within him and a friend or a THICK-UN to stand by him, he is a poor, weak, cross-grained fool to refuse.
1888. PAYN, The Eavesdropper, II. ii. Can you smash a THICK-UN for me? inquired one, handing his friend a sovereign.
1896. FARJEON, The Betrayal of John Fordham, III. 277. With three peas and a thimble Ive earnt many a THICK UN.
1897. MARSHALL, Pomes, 26. He wanted his THICK UN to canter home with forty or fifty more.