The plant
Cannabis Sativa, or the dried leaves thereof.
This is a common name in South Africa, indeed in all of Southern Africa for the smokable, intoxicating herb also refered to as weed, grass, doob, green, marijuana, etc.
This word is used in English, Afrikaans - heck, anyone in this part of the world will know what you mean if you pronounce it right. For the pronounciation, think ducker, but replace the ck with a velar fricative (see Afrikaans).
Common varieties include Malawi Gold, Swazi Skunk and Durban Poison.
The name is also used for several plants that bear a resemblance to Cannabis Sativa, though they are not closely related and are not smokable, for instance Red Dagga and Wilde Dagga.
The South african Government does not view dagga as "relatively nontoxic" - like almost everywhere else, it is illegal here, even though it is increasing argued that smoking Dagga is relatively harmless, and has been a part of traditional African culture since long before it was outlawed by the colonial overlords. One could argue that not much has changed since then, seeing as worldwide drug policy is set by the United States of America.