Funsponge 

This word is used when a person sucks up all the fun out of a room and makes the atmosphere really boring

Like the way a normal sponge sucks up liquid

Sean is so dull, he's being a total funsponge.

Sean was being a total funsponge when he started talking about math

Funsponge by Sexylegs April 17, 2009

Military Fun Sponge 

A fun sponge in the military is a socially inadequate, humourless & deeply unpopular person who, through a sense of bitter loathing & revenge, sucks all the fun out of everything. Normally calls senior officers ‘sir’ on twitter.

Dude: why don’t we show our human side & engage online?
Military Fun Sponge: all this social media stuff is only a passing fad & has to be boring.

Military Fun Sponge by Bumsnorkler December 3, 2019

funmonger 

Slang for a person who is selling fun, often with no regard for safety or sensibilities.

She was a shameless funmonger, selling pleasure to the most desperate of people, at the saddest of times.

funmonger by Dr Bunnygirl September 5, 2019

Fun sponge 

Noun. A boring, humourless person.

Who was that boring prat you were with yesterday? He was a real fun sponge!

Fun sponge by Dick Wright-Upham December 7, 2010

Fun Sponge 

The character Freddie Mclair from the television show Skins.

Cook: And why didn't we invite Freddie?
JJ: Cause he's a Fun Sponge
Cook: You got it

Fun Sponge by seemejudgingyou September 8, 2009

fun sponge 

Someone who has the ability to walk into a room and litteraly soak all of the fun out of it. Also known as a muzz.

"Nick was such a fun sponge, the moment he arrived the party died."

fun sponge by Doc Raymond October 10, 2003

Fun sponge 

A person or group of people, who take an activity so seriously and or literally, that they squeeze every last drop of joy out of it.

Can be appropriately applied to cyclists who spend 10K+ on their bikes, clearly don't enjoy what they're doing and live for looking down on those with 'lesser' equipment.

"Did you see those Joe Serious bellends shaking their heads and tutting?"

"yeah, fun sponges every last fuckin' one of 'em"

Fun sponge by Itsallgoodman May 17, 2016