Green’s Dictionary of Slang

1. absolutely exhausted, metaphorically brain-dead from overwork.

1998		I. Welsh Filth 286: You were trying to tell me the other night, but I was cabbaged.
2001		K. Sampson Outlaws (ms.) 150: Half fucking cabbaged from zero sleep and endless nightmares.

2. rendered imbecilic.

2000

N. Griffiths Grits 319: Ee hit the rocks an apparently ee’s cabbaged now, a vegetable. Irreversible brain damage like.

3. (also cabbaged out) drunk or drugged.

2000		N. Barlay Crumple Zone 71: I get back from Sabine’s, maybe around one, pretty cabbaged, drunk enough for Alv to drive me back the ten-minute walk.
2003		McGill Reed Dict. of N.Z. Sl. 42: cabbaged is made mellow if not sluggish by smoking cannabis; cabbaged out is to be affected by cannabis to the point of being almost comatose.
2013		K. Sampson Killing Pool 248: Me off my cake, grinning into the camera, big mad cabbaged grin on me.