From Wiktionary, the free dictionary
Shortening of abseil + off.
ab off (third-person singular simple present abs off, present participle abbing off, simple past and past participle abbed off)
- (British English, transitive, slang, mountaineering) To abseil down a mountain.
- Synonym: rap down
1995, Matt Sarnet, Climbing: Issues 151-153[1], page 93:Every one's up on a crag where he'd got stuck and had to ab off.
2009, Andrew Grieg, Summit Fever[2]:Two of them abbed off to leave enough for the other two.
