DC AC - noun phrase (humorous) - The primary mechanism of air conditioning inside the DC Beltway.  Notionally, the movement of air due to revolving doors caused by the never-ending cycle of contractors becoming civil servants, civil servants becoming lobbyists, and lobbyists forming startups and becoming government contractors once more.

profit harvesting - noun phrase - A polite name for the act of finding each and every little remaining way to gouge money from someone or out of some thing.  Called nickel and diming when hard currency was more common.

disasterbation - noun - Idly fantasizing about possible catastrophes (World War III, EMP strikes, nexus collapse, civil war, simulation hypothesis system shutdown, full-blown hyper-blight) without considering their likelihood or their possible solutions and preventions.  Very common in the prepper and futurist communities.

Source: M. Alan Kazlev (updated a bit and cross-referenced by me)

@here grenade - noun phrase - The act of tagging a message @here (meaning, everyone) in a crowded Slack channel (users >= 100), causing everyone who's busy but monitoring to drop whatever they're doing and flame you for bothering them by messaging @here.  Normally done by a user trying to get a response to a maximum severity ticket that's been ignored for longer than the SLA.

Example: "PFY threw an @here grenade into the #tech-support channel because the border router was on fire and the admins on call were ignoring their pagers.  He got kicked but at least the outage is over."

Proper channels excise tax - noun phrase - The markup paid on commonplace things when you go through proper channels at work to do something rather than going rogue, buying it yourself and filing an expense report.  For example, a flight from Chicago to Boston might cost $176us if you paid for it yourself, but by using your employer's internal processes and vendors the cost of the same flight is closer to $630us.

Trapdoor goalposts - noun phrase - When two or more requirements are set up so that meeting one automatically means failing another. This is a bad faith argument whereby it is impossible to meet the requirements someone sets, without admitting refusal to allow the outcome the other person desires.

Example:
"If you're making a decent income you can't possibly talk about poverty, you don't know what you're talking about."
"I'm actually below the poverty line."
"You just want a handout!"

Taxonomic debt - noun phrase - The time you spend learning arbitrary jargon at a new job.

Source: Bradford Stephens
 

technical heresy - noun phrase - Openly demonstrating the imagination to come up with actual uses for a platform or application that it is currently popular to hate.

maintenance contention - noun phrase - When there is only one bathroom but two people need it for the exact same urgent thing.

rotten egg dependency - noun phrase -  A service that a mission-critical application relies upon that nobody knows about but brings everything to a screaming halt when something happens to it.  In a sane world, said dependency should have nothing at all to do with the thing that just crashed.  Called this because it's as pleasant a surprise as a rotten easter egg at breakfast.  Best explicated by the following haiku:

It's not DNS
There's no way it's DNS
It was DNS