Green’s Dictionary of Slang

Guinea n.¹

(US) a euph. for hell, e.g. in phr. go to Guinea.

1899

Ade Fables in Sl. (1902) 78: Now and then remarking to Himself, ‘Well, I’ll jest swan to Guiney’.

SE in slang uses

In compounds

Guinea ship (n.) [SE Guinea ship, a ship bringing slaves – in terribly crowded conditions – from West Africa]

(W.I.) a crowd, a large number of people.

1924, 1956

cited in Cassidy & LePage Dict. Jam. Eng. (1980).