What's the difference between those words for drugs/narcotics: やく(薬), according to tangorin.com and jisho.org is a slang word If you type narcotics into Jisho.org it suggests ドラッグ, and there is also an option of まやく (麻薬). If I wanted to talk to my teacher about drugs, which form would be the most appropriate? What about a discussion between colleagues? For example, "I don't think all drugs are evil" or, jokingly, "If you want to be constantly happy just take drugs all the time"
Basically, narcotics can be translated as 麻薬, which at least includes opioids like morphine and cocaine, but does not usually include 覚醒剤 like amphetamine or so-called 合法ドラッグ (legal drugs). If you need to use these terms strictly and professionally, you'll have to read serious review articles carefully, since it's "officially defined" in different ways by various organizations and laws.
If you don't need to be an expert, these are the common options which should satisfy most people:
- ドラッグ: It's a generic term for any kind of high-risk chemical agents (except tobacco and alcohol) which is used to make people "high." It can safely be used in formal discussions with your teacher. This word almost always refers to the high-risk intoxicants. Probably the sole exception to this is ドラッグストア, which is pretty much like English drugstores.
- 薬物【やくぶつ】: Almost the same as ドラッグ, but preferred in legal or academic contexts. For example, 薬物中毒 ("drug intoxication"), 薬物の乱用 ("drug abuse"), etc.
- 麻薬: It I think is the primary translation of narcotics. Most people vaguely know that 麻薬 is a certain subset of ドラッグ, but I think very few can explain the difference well. Therefore 麻薬 is used to refer to any intoxicating drugs in general.
- 薬【くすり】: It usually refers to the medications available in clinics and legal drugstores, but as a slang term, it can (euphemistically?) also refer to illegal/high-risk "drugs", depending on the context. In slangy conversations I feel 薬 is more common than the stiff-sounding ドラッグ/麻薬/薬物. やく/ヤク is probably jargon actually used by some underground folks, but I believe most people have heard it only in yakuza films, police dramas and such.