Green’s Dictionary of Slang

(W.I. Rasta) a disdainful expletive, a very common, mild excl. of impatience, vexation or disappointment.

1827		Hamel, Obeah Man I 247: ‘Lord! I would not let him kiss me, if he was a white man; much less since he is a Mulatto.’ [...] ‘Cha! cha!’ replied Drybones; ‘you all run after him as soon as you see him.’.
1858		in Trinidad Sentinel 8 Apr. n.p.: Cho! da massa wha da command Port a Spain Gazette, he no hab sabby nuf fou massa Hinde.
1862		Capt. Clutterbuck’s Champagne 48: She smote her upraised foot smartly on the ground, and uttered the monosyllable ‘Chaw!’ Miss Rosabella was displeased. [Ibid.] 123: Domingo [...] had nothing for it but to ejaculate ‘Cha!’ and make a lingering retreat.
1869		H.G. Murray ‘Tom Kittle’s Wake’ in D’Costa & Lalla Voices in Exile (1989) 104: Cho! him put on de pur when him most catch, maam.
1873		C. Rampini Letters from Jamaica 217: ‘Cho!’ replied Tiger.
1909		‘Tom Redcam’ One Brown Gal 110/1: Cho man, Big Massa gib Backra brains to mek law and gib Black man brains to find out how to bruck it.
1913		H. De Lisser Jane’s Career (1971) 75: ‘Tcho!’ exclaimed Kate.
1939		A. Durie One Jamaica Gal 15: ‘Cho man!’ he exclaimed, ‘You t ’ink I gwine consort with dat gravillicious female?’.
1943		C. Thompson These My People 21: Cho! who dah worry ’bout Amos?
1958		J. Carew Black Midas 277: Chu, man. What you grumbling ’bout.
1975		J. D’Costa Escape to Last Man Peak 152: Cho, dat’s not’ing!
1986		R. Hewitt White Talk Black Talk 60: When you walk past you see ’em and they say, ‘Cha! What you doin’ over dere wi’ dat white man.’.
1986		O. Senior ‘Ballad’ Summer Lightning 115: Cho! Miss Rilla have better things to do with her time in heaven.
1990		L. Goodison Baby Mother and King of Swords 23: Chuh you hear that Sylvyie, me come a town come tun Deejay you know, coulda cut a chune, ‘Make them hear, for me no care.’.
1994		M. Montague Dread Culture 131: Dem tear down me gates and find mi rings and two weights of herbs. Cho!
2000		N. Hopkinson Midnight Robber 66: Cho, me ain’t business. He coming or what?
2006		Cham ‘Fat Punnany’ 🎵 Cho! I can’t speak mami, give me a peep mami.