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1.
A very nice and loyal friend who cares for others more then he does for himself.

Gets into a lot of trouble
Sleeps during language classes
Loves sports
Most of all he is a hardcore Indian!!!
Speaks too much
"muthu!" stop sleeping in my class!!!
Dude your addicted to sports like muthu!
Wow you fell asleep again! What a muthu!
by Sham425 July 02, 2009
 
2.
Can be used as a noun (n.), a verb (v.), or an adjective to describe anything which sleeps or tends to sleep. This is a very broad term, and covers the gamut for all living beings in this world that sleep or tend to sleep. The name comes from our friend Muthu, who consistently sleeps, no matter any good or fun situation with his physical and mental clumsiness and ineptitude, degrading the quality of staying awake and marring people's moods to sleepiness.

Or, can be used to describe as someone who shamelessly flirts with girls no matter what his age is.
(n.)
1. I can't believe you just slept of during my lecture. You're such a Muthu.

(v.)
2. You better be careful with those mega-serials and tv soap operas, or you might just Muthu it up.

(adj.)
3. Man, Dinesh was being so Muthuite when he was talking to sruti earlier.
by BhuBhu June 28, 2006
 
3.
Indian meaning of Matthew. Means a gay person with the ability to control ejaculation whenever needed.
What the sardine bread!! Stop muthu-ing all over the floor!
by ieatsardinebread May 07, 2010