Green’s Dictionary of Slang

(US) pompous, verbose; also as v.; thus spreadeagling/spreadeagleism n., pompous talk.

1856		Wash. Sentinel (DC) 12 July 2/6: Six half-horse, half-alligator men from Kentucky [...] will put to flight all the loud-talking, spread-eagle Free-soilers and Abolitionists.
1862		J.R. Lowell Biglow Papers 2nd series (1880) 104: They can’t help spread-eaglin’ long ’z ther’ ’s a mouth.
1869		F. Whymper Travel and Adventure in Alaska 309: If a preacher, actor, or writer indulges in an exaggerated manner, they say ‘he piles on the agony’ too much, has a ‘spread-eagle’ or ‘high-falutin’ style about him.
1878		J. Hatton Cruel London III 270: Don’t let us have any spreadeagleism.
1884		(con. c.1840) ‘Mark Twain’ Huckleberry Finn 171: The duke [...] read the parts over in the most splendid spread-eagle way.
1899–1900		C.L. Cullen Tales of the Ex-Tanks 130: You can’t spreadeagle this outfit by going at a talkfest both ends from the middle.
1926		Wood & Goddard Dict. Amer. Sl. 6: blah. Bunk, nonsense, spreadeagle talk.