lun, n. — Green’s Dictionary of Slang

lun n.

[UK theatrical manager John Rich, who in 1717 as ‘John Lun’ performed as ‘Harlequin’ in a new style of entertainment he called ‘pantomime’]

Harlequin, the commedia del arte stock character; by. ext. any stage clown.

1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1811		Lex. Balatronicum.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.
1859		Matsell Vocabulum 52: lun The funny fellow; a clown.