Shunday 

The day that you turn off your communications equipment to avoid all contact with other people so you can do 'your own thing'.

I was so tired after a tedious week at work I decided to take a shunday...

Shunday by inx13 February 8, 2010

Shunday 

The voluntary act of shunning all social, physical and intellectual activities on a Sunday

Exhausted after a hectic week-long travelling schedule, she decided that it would be a Shunday this time

Shunday by cyclopsee July 18, 2011

Spite Monkey Sunday 

Spite Monkey Sunday is that day of the week when all the brain dead little losers try to get definitions accepted by Urban Dictionary. They try to get a flattering definition accepted, of themselves if they haven't got any friends, or of some female if they think it will help them get into her knickers. Why? Usually because they’re back at school on Monday and are trying to make themselves look good, the poor little winkies. Then the unthinkable happens, they’re definition is rejected because it doesn’t conform to the rules laid down by Urban Dictionary. Oh Calamity! So the silly little wank biscuits throw a hissy fit, go into a session to vote on the inclusion of new words and reject everything without bothering to read it. Then comes Monday and these sad little gleets go back to school and bother the human race somewhat less than they do at weekends.

“Couldn’t get a thing accepted on Urban Dictionary, it was Spite Monkey Sunday.”

Spite Monkey Sunday by AKACroatalin April 27, 2015

Sod All Sunday 

Definition---
An entire Sunday day which passes where absolutely nothing transpires; A miscreant day which you will never remember; A Sunday which is sullied away to pyjama wearing and not bothering to lift ones arse away from the sofa for more than a toilet visit. The phone does not ring and your mobile is not blessed with anything other than a full battery.

Example---
Dan: How was your Sunday? Get up to much?
Garath: Good mate cheers, I had a sod all Sunday.

Sod All Sunday by Gwendolenalexia July 31, 2012

Stunday

A Sunday which involves significant amount of studying

Paul: “Are you coming out to walk the dogs in the park?”

Claudio: "Ah, sorry. My favorite study streamer is online. I am going to spend rest of the Stunday at home."

Stunday by nish-ant May 2, 2021

sunday curse 

having school or work on monday, and not being able to get to sleep on sunday.

usually it carries over, and makes it really easy to get to sleep on monday night, although sometimes a little too early

I got 3 fuckin hours of sleep last night because of the damn sunday curse

sunday curse by diddy kong September 22, 2007