A mushroom is guy who is unattractive overall without any redemptive qualities (such as good personality, charisma, sense of humor, smells good). They are just full of cringeworthy qualities such as:
Being painfully ugly
Lacking hygiene
Messy appearance
Typically shy
Arrogrant

If there is something good about him that makes him tolerable, then he is probably not a mushroom.

The female equivalent is a moth.
"God, I hate Charlie. He's ugly, almost obese, rude, and smells really bad."

"Golly Jennifer, why are you even friends with that mushroom? All he does is play video games and avoid daylight. "
by misterxoxo November 19, 2015
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A person with absolutely no personality who soaks up personality from other people, especially people they are dating. This would include interests, sense of humor, fashion sense, etc.
The best celebrity example of a mushroom is Brad Pitt. You may notice that he changes the way he dresses and his interests based on who he's dating.

Used in a sentence: James claimed he like strong personalities, but his current girlfriend is evidence that he likes mushrooms.
by Serendipity99 July 5, 2007
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a poisonous fungi grown mostly in shit or on damp logs, that makes you get in touch with your holographic spirit, oh and you trip. the trip lasts for 4 to 8 hours. try some dutch shrooms. goddamn.
by lefty September 16, 2003
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An individual who is closely tied with their origins. So connected to their roots, they stubbornly refuse to live outside of their surroundings. Despite opportunities in other lands, the individual will not migrate. ,affection, lover, immigration, urban, artist
The artist will not blossom abroad, simply because he is a mushroom.
by Ola Plum March 31, 2008
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you ex-boyfriend or ex-girlfriend, or whoever really likes you and you lay down the law and will not let you go. they are a fungus like, as in gross, and are stuck on you for what feels like forever. they seem to not want to move on at all, when you are already over them.
1. This boy kyle is a mushroom! he will not move on!
2. My ex-girlfriend is being such a mushroom, man.
by Abbay June 14, 2007
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A way to masturbate where you hold the shaft and rub the tip of your penis in a circular motion.
The mushroom is one of the best ways to masturbate.
by hqwfhf May 24, 2008
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