A military term, meaning to take note of the current time.
If a circuit breaker pops, take a time hack and then wait two minutes to reset it.
Heard from a soldier, possibly comes from the Army. When you got a guy whose got his clock set juuuust right to miss shit, and his excuse is that his watch is set wrong.
Yeah, these guys are an hour late for the patrol brief. I'm thinking massive time hacks, guys.