Green’s Dictionary of Slang

a foolish person.

1869		C.H. Spurgeon John Ploughman’s Talk 101: Poor sillies, they have wind on the brain.
1870		E. London Obs. 19 Mar. 7/1: The innocence of the poor old silly was downright touching.
1880		G.R. Sims Three Brass Balls 86: And you’re a dear old silly.
1885		W.H. Stead ‘The Profits of a Procuress’ in Pall Mall Gazette in Metropolitan Poor III 35: It depends upon the trouble which we have, and the character of the girl. Some girls are such sillies.
1900		Marvel XIV:356 Sept. 11: The young lady will be chaperoned [...] by that engaging old party who stopped her making a silly of herself the other night.
1902		Bulletin (Sydney) 9 Aug. 14/4: The recently-returned boys in khaki have been doing Collins street, and imagining their mustard puttees were ‘killing’ all the syrens of The Block. [...] The glory of the returned contingenter has long since passed away. The ‘son of the Empire’ is now regarded as somewhat of a silly.
1909		L.W. Payne Jr ‘Word-List From East Alabama’ in DN III:v 369: silly, n. A silly person or fool. ‘Go and do it yourself, you silly.’.
1910		‘Doss Chiderdoss’ ‘The Sweetshop Girl’ Sporting Times 5 Mar. 1/4: Is the sweetshop girl a silly to encourage Gus and Willy?
1916		H.L. Wilson Somewhere in Red Gap 77: Ain’t I the old silly!
1920		E.F. Benson Queen Lucia (1984) 130: He has made such sillies of you all.
1923		‘Sapper’ Jim Maitland (1953) 185: ‘What on earth were you doing there?’ ‘Buying hats, silly, and other things.’.
1925		S. Lewis Arrowsmith 254: Do you think I’m an awful little silly?
1930		E. Waugh Vile Bodies 170: No one wants to keep you from your wife, you old silly.
1936		J.T. Farrell World I Never Made 428: Why, Daniel, you’re an awful silly.
1940		M. de la Roche Whiteoak Heritage (1949) 60: She was a silly.
1942		(con. 1890s) S. O’Casey Pictures in the Hallway 26: Johnny felt sorry over his Ma an’ Ella makin’ such sillies of themselves.
1947		‘F. Bonnamy’ Self Portrait of Murder (1951) 37: Go on home, you big silly.
1953		J. Thompson Alcoholics (1993) 88: They were such sillies.
1958		(con. 1940s) B. Behan Borstal Boy 161: Come on, you silly old silly.
1958		R. Prather Scrambled Yeggs 57: ‘What are you trying to do, woman?’ I asked her, ‘get me drunk?’ ‘No, silly. I don’t know; I just feel like getting a little stupid. Numb.’.
1967		I. Rosenthal Sheeper 31: Pish, little sillies, it is only a skunk.
1978		P. Theroux Picture Palace 57: Over here, silly.
1987		B. Chatwin Songlines 24: You’re late, silly!
1999		K. Sampson Powder 366: It’s me silly! Open up.
2014		D. Jenkins His Ownself 223: Yeah, I’m aware the college game has its share of sillies. But the college sillies aren’t just cheering for the team. They’re cheering for the campus, the drag, the old school colors, the memories.