Noun: any fortunate event or achievement that is a result of luck.
Verb: To achieve something good or end up in some good circumstance by sheer luck.
The term has its origins in the Spanish
verb "cagar" which means "to take a crap, to shit, to defacate".
In English, when something lucky happens or is accomplished,
one might say that it was "pulled out of (a person'
s) ass". The idea is the same with "cag".