Flat Chat 

When someone is extremely busy

He is flat chat on other work today and will get back to you tomorrow.

Flat Chat by odelay May 6, 2012

FLAT CHAT 

Adjective:
Feigning importance and fraudulently or deceptively claiming to be busy at work when in reality you have sweet FA work to get done.

Synonym: Pretending to be busy at work when you actually are not.

"How are you going today?" "Oh, I'm absolutely FLAT CHAT!" (Sigh dramatically and flutter hand over chest)

FLAT CHAT by Cactus Juice February 22, 2018

flat-chat 

An Australian slang word meaning to go at the maximum speed possible. To push yourself or your vehicle to the extreme of velocity.

"Wow, that car is going flat-chat! It's out of control!'

flat-chat by Sir Glame November 14, 2010

flatchat

At full speed, going as fast as you possibly can. (Australian)

"We were fully gunning this old HQ Kingswood totally FLATCHAT downhill with a tailwind, and we still couldn't get away from the copper on his pushie."

flatchat by Alex From Oz October 20, 2007