Slang for marijuana: Deew is the backwards spelling of "weed." Historically, its proper usage was to conceal the word "weed" in circumstances when saying "weed" would be inappropriate or undesirable.
Nowadays, once usage has been established, it can be used to mean "weed" in any circumstance whether or not for the purpose of concealment.
The pronunciation of "deew" is the same as "do." "Dyu," as in "few" but with a "d," is a less common, but equally acceptable pronunciation. The official spelling of the word is "deew," but when written and the objective is still to conceal "weed," "dew" is also an acceptable spelling.
To further conceal "weed," "deew" may be used interchangeably with "mountain dew," or in exigent circumstances, "mountain deew code red."
Additionally, "emoks" (pronounced e-mox), a derivation of the backwards smelling of "smoke," can be used in conjunction with "deew" to form phrases such as "lets go outside and emoks some deew," or "this is the best deew I have ever emoksed."
The origins of the term are mysterious, but spectators believe the "Charter" chapter (Irvine, CA), of the Skubaz organization may be responsible for its creation and/or its emergence in pop culture.
Dude and Guy are at Dude's house with Dude's parents around.
Guy: What do you feel like doing right now Dude?
Dude: Umm, you want to go to Bob's place, he has some good deew.