Green’s Dictionary of Slang

1. the fig. world of innocence; thus greenlander, a gullible, innocent person.

1838		Dickens Oliver Twist (1966) 103: ‘Where did he come from?’ ‘Greenland. Is Fagin upstairs?’.
1848		Ladies’ Repository (N.Y.) Oct. VIII:37 316/1: From Greenland, A man who is not initiated, or does not know much.
1864, 1867, 1870		Hotten Sl. Dict. 147: GREENLANDER, an inexperienced person, a spoon.
1891		Exeter & Plymouth Gaz. 15 Oct. 6/4: You think I come from Greenland. You think I’se sart [i.e. stupid], but I ain’t so sart as you thinks on.
1967		Anthony Burgess ‘Rosetalk’ in Oz 6 22: greenland; The psychodelic [sic] visionary world.

2. (US) Ireland; thus Greenlander, an Irish person; from Greenland, used of an unsophisticated, ignorant person [also play on SE green, Ireland’s national colour].

1873

Sl. Dict.