AFF

AFF: abbreviation for "Away for Flow", which indicates that the person is being in the zone, thus, shouldn't be disturbed (hence the "away").

In this era of remote working where a coworker does not necessarily know the physical state of another coworker, this abbreviation can be used to politely hang/reject a conversation (or chat) when the person is being focused (i.e "AFF, will reply later").

About flow: "flow, also known colloquially as being in the zone, is the mental state of operation in which a person performing an activity is fully immersed in a feeling of energized focus, full involvement, and enjoyment in the process of the activity." (Wikipedia, at en.wikipedia.org/wiki/Flow_(psychology))

Example 1
A: "Can you go get some documents outside?"
B: "Sorry, AFF. Will do it later"

Example 2
A: "Yo guys, I'll be going AFF. Will be back after lunch"