utter nonsense 

When someone makes up a silly little definition you tell them that they are talking utter nonsense.
Strangley enough, the majority of definitions on Urban Dicitionary fall into that category.

Have you seen Urban Word of the Day? Its Stanky Leg.

Stanky Leg - what on earch is that?

I know!!! Utter Nonsense

utter nonsense by ledge67 February 19, 2009

utter trash 

Someone who’s hideous

Brielle is utter trash.

utter trash by Big dumb November 3, 2019

Utter Madness 

just fucking shit up.

just won't go to sleep that night as a result, probably bang the brains out of his girlfriend too... just utter madness

Utter Madness by JayGatsby2454 April 13, 2010

utter destruction 

Everything destroyed

The utter destruction of all the rainforests.

utter destruction by Julithefinder May 27, 2016

Utter chalice 

Stuff that is crazy ass shiznit!

That crash was utter chalice!

Utter chalice by Jigs February 11, 2003

utter pish 

Talking nothing but pure drivel, being wrong. (1)

Also, you can use it when calling bullshit on a game or something. (2)

(1) You're talking utter pish!

(2) That's utter pish, sparks were flying off his head. He's well died!

utter pish by Bazza Cribbons November 7, 2013

Utter Shit 

When something is beyond being simply crap, rubbish or even shit.
It then becomes Utter Shit, the absolute pinnacle of crappiness.

"Hi there Hywel, what do you think of the new Facebook user interface"

"The NEW Facebook user interface is utter UTTER SHIT. It's aimed at people who use phones and tablets and NOT people who use web browsers which can actually do context based browsing and not the stupid context less browsing that the phones are designed to do. It is SHIT of the brownest and smelliest... despite its stupid teletubby rounded button look."

Utter Shit by Scurlage September 9, 2020