Can also be used with a comma: AOT,K.
The contraction is been used in a number of ways, but most specifically:
1. To convey a vacuousness, or general lack of thought or intelligence
2. As an all-inclusive, or "all of the above," especially to questions of ignorance, arrogance or blind faith
Q: What is this guy? A cretin, a moron, a dimwit or an idiot? A: AOTK.