couldn't be rat-arsed 

In other words, couldn't be bothered.

We tried to get him to send in the form on time, but he couldn't be rat-arsed.

couldn't be rat-arsed by Fearman May 24, 2008

g-rat 

grace is a g-rat. The g-rat is a rare species, it likes to nibble on pellets, and can often be found fornicating with the skel-rat species.

yo brother stop acting like a g-rat you'll scare everyone away

g-rat by attack of the g-rat September 14, 2008

Bilge rat 

Someone who doesn’t own a boat or has no intention of ever owning a boat but enjoys fishing and will do anything to go out in his friends or acquaintance’s boats.

Jordan is a real bilge rat.

Bilge rat by Barracod May 20, 2019

Flying Rat 

The person using jetpack on MLG Sanctuary in the hit game Halo: Reach

Flying rat sniped me again!

Flying Rat by BbyBackBic November 8, 2014

A Rat 

honestly he’s like 6 years older than me so I better shut up. Ben of the Week Ben De Almedia

Some kid: EW ITS A RAT
BenoftheSQUEAK: SQUEEEAAAAKKK

A Rat by Qwerjfbfbbfbff October 18, 2019

mo rat

Militia rat. Someone who always doing militia activities. mall rat

You're a mo rat aren't ya.

mo rat by Gilcrest March 8, 2004

i couldn't give a rat's ass 

An expression meaning I couldn't care a less or give a shit about something.

Worker: "I was late to work because my car broke down goddamit!"

Boss: "I couldn't give a rat's ass if you got anally raped this morning! You're fired!"

i couldn't give a rat's ass by Human Pickled Punk May 15, 2016