To fail a drug test or piss test. Drug tests are usually given by either a probation officer or a parent/guardian. The test requires for you to urinate in some sort of container, while afterwards your urine is tested for illegal substances. If you test positive for any illegal substances, you just dropped dirty.
Dude, my PO is comin' tomorrow. I'm gonna drop dirty for sure.
by Miss Kristin July 18, 2006
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you failed a drug test

you pissed in a cup and it came back dirty meaning you failed your drug test
Shamika dropped dirty in her PO's office... agian
by Joe Schaefer July 18, 2005
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A killin 5-piece rock/jam/funk band from New Brunswick, NJ. Check more out at www.thedirtydrop.com.
Don't bother taking a shower before The Dirty Drop plays, you're just going to be filthy afterwards anyways...
by the ketchup July 11, 2008
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A urine test that reveals evidence of narcotics.
if you smoke weed and take a drug test you are likely to get the "dirty drop".
by Anonymous May 16, 2004
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Serial position in which a penis-haver lies recumbent and holds his erect membrum virilis pointing upwards. The partner, having eaten a vindaloo the precious night, squats about the erect "gherkin" and drops the drty bomb.
Oh my goodness, a roffer is about to drop a dirty bomb on the gherkin!!
by ORANGEHAMSTER ALAN ORLA May 17, 2023
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