Usually being on a "mission" refers to be searching for any kind of drugs, but can also mean looking for other things.

Yo, I'm on a mad mission to cop some weed, bro.

Hey, did you just see some kids pass by on a mission?
by AC November 16, 2006
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One of the central districts of San Francisco, CA. It is the city's Latino district. It is famous for its historic buildings, its Mission burritos (the best in Northern California), and its murals.

Rich people who tour San Francisco for a limited time think that the Mission is the ghetto. That's kind of true, but the disdain some of these people take with them is unfortunate. The Mission district is large and complex, with variying socioeconomic areas, clusters of mini-communities, and several specialty stores found nowhere else. Native San Franciscans know it as one of the "cool" districts.
SF Person 1: My cousins from San Mateo are going to visit the city this weekend; I'm gonna take them to The Mission!

SF Person 2: Ah, The Mission! I want to go to The Mission, too!

SF Person 1: Come with us!

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Cousins from San Mateo: Ooh... is that graffiti on that tree? Oh no, are we going to be mugged? Why is that corner store selling guavas?
by Gukumatz June 25, 2006
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A once great and 'vibrant' (read 'ghetto') district of San Francisco now being taken over by an invasion of carpet-bagging, carpet-munching, cracker-ass hipsters.

SFC Native #1: It's cool how The Mission is coming up and crime is going down.

SFC Native #2: Nah fooh, the rents are rising and there's all these annoying young gringos stupidos around, not the older kind that were just annoying but not stupid.

SFC Native #1: Yeah, I guess you can't have everything.
by Mescalito April 17, 2008
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U.K South London slang

word describing a long amount of time taken to get somewhere

From the idea of a mission being something which takes along time to complete.
Beckenham! Ah Bruv das missions!
by Gigi July 13, 2004
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A method of describing a journey or task or great difficulty, boredom, or length.
"We had to pick up, mission it all across town, and drop off in Lizzie's."

"I'm on a damn mission with the wind blowing." (ie: Rolling in the wind.)
by Ian February 20, 2004
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To go on a mini-expedition. This might involve negotiating treacherous terrain, having strange adventures and meeting random people. It will definitely involve having an amazing time...
I had the most amazing day missioning
Let's go missioning again really soon
by SE Shell September 18, 2009
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A very arduous task. A job that is very strenuous, and takes a long time to complete or even to attempt.
"Write a 5000 word essay? What a mission!
by NZAzN K' October 19, 2003
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