1 Broken, smashed or beaten up to the point of being visisbly altered, unusuable or non-functional.
2 Intoxicated with drink or drugs to the point of non-sensibility.
3 Resoundingly beaten in a competition of some kind.

As far as I am aware this term comes from the German footballer Gerd Muller who scored lots of goals.
I got totally mullered last night, I had loads of pills......

A bus smashed right into his car and absolutely mullered it....

We got bloody mullered at five-a-side, 10 bleedin' nill

This term probably comes from German international footballer Gerd Muller who used to destroy teams with his sizzling shots from inside or outside the penalty area....

Gerd Muller, known as "Der Bomber", is the greatest goal-scorer of the modern era. He scored an amazing 68 goals in 62 games for West Germany during the 1970s, including the win in the 1974 World Cup Final.
Gerd Muller, a stocky, powerful striker with matchless speed in the penalty area, amassed 628 goals in first class football. This included 365 goals for Bayern Munich during his 14 year career.
by james mcdonnell March 16, 2004
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It can also mean mashed, beaten or broken up.
I mullered the car the other day.

This guy came into the pub and just mullered this other geezer.
by Anonymous November 04, 2003
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I've always taken it to mean generally either fucked up or fucked over. It doesn't have to be related to drink or drugs.
Spurs mullered Man City in the first half – it's unbelievable that they still managed to lose.
by Gravy February 05, 2004
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To be absolutely off your face on drink and drugs, derived from the Yoghurt manufacturer Muller, after people (mostly gimps) used to go round sayin Creamed, Creamed turned to Mullered
" I was fackin mullered on friday night in the club, I was so facked that I started usin cockney words like Mullered "
by John Gaskell October 27, 2005
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How one feels after taking a lot of ecstacy and / or amphetamines.
We were all mullered when we got back from Bullet Proof at 7am.
by Dan Fox June 24, 2003
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To be stitched up (tricked, set up). (original meaning circa 1960-1990)
From the range of Muller Saddle stitching machines found in nearly every print company, used to secure paper to make booklets.
In recent years it has come to mean drunk or rekt
That bloke absolutely mullered me last week when he new i was desperate for those wheels. He nearly doubled his price, the geezer.
by stan francisco August 17, 2018
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