Green’s Dictionary of Slang

ignorant adj.

[dial. ignorant, uncouth, ill-mannered]
(W.I./UK black)

1. angry, irascible, short-tempered.

[WI]H. De Lisser Jane’s Career (1971) 58: See here, Miss Mason [...] I tell y’u not to abuse me, for I will get ignorant again.
[WI]S. Selvon Lonely Londoners 39: One day a Jamaican fellar come in and get ignorant and start to make rab.
[UK]Indep. Rev. 10 June 4: Ignorant: easily angered (black Eng).

2. unpleasant.

[US]A. Young Snakes (1971) 127: I come up here for a piece of tail and get mixed up in some old ignorant murder shit!

3. arrogant, ill-natured, bullying.

[Ire]Share Slanguage.

In compounds

ignorant oil (n.) (also ignite oil)

(US black) alcohol.

J. McShann [song title] Hootie’s Ignorant Oil.
[US]N. Heard Howard Street 87: That ignorant oil might clear your head some.
[US]R.D. Pharr S.R.O. (1998) 15: What goddam right did Sid Bailey have to cry? Wasn’t it his goddam money that bought the goddam ignorant-oil?
[US]E. Folb Runnin’ Down Some Lines 187: Hard liquor also had its own vernacular labels – oil, ignite oil, do-it fluid.
ignorant stick (n.) [var. on idiot stick under idiot n.]

1. (US) a mop.

Amer. Record Guide 11-13 212: Get the Mop (the ignorant stick) [...] highlights the bass and rhythm section and recalls Woody Herman's new treatment of his rhythm section.
[US]Billboard 9 Feb. 31: Featuring J. C. Higginbotham BUZZ ME GET THE MOP (The Ignorant Stick).

2. (US) a shovel; a long-handled hoe.

[US]J. Blake ‘Day of the Alligator’ in Algren Lonesome Monsters (1963) 133: Well, play me a tune on that ignorant stick you got there.
S.L. Twin Out of the Bleachers 80: We used a long hoe called ‘the ignorant stick’.
B.W. Bell Clarence Major and His Art 23: A black man dressed like an English gentleman is bludgeoning a poor, suffering white man over the head with an ignorant-stick.

In phrases

ignorant as Paddy’s pig (adj.)

see under Paddy n.