How offensive is the expression 他妈的? What is an English expression with a similar degree of offensiveness? In what situations is this expression appropriate / not appropriate?
It is very common and, in my personal experience, has similar offensiveness as the f word in English.
It can be offensive and quite rude: e.g. in a business negotiation, when the deal is finally broken and one side says:
你他妈的给我滚出去 = "Get your fucking ass out of my office"
It may be used in irony among close friends which is not offensive then: E.g. when two close friends meet after a long time, one may say:
你最近死哪去了? 他妈的都忘了哥了! similar as "Where have you been lately? I fucking miss you!"
Hope this help to get the points.
Since new swearing tag appears thick and fast...
他妈的is already sounds traditional...
It could come out of a gentleman's mouth,like the essay wrote by the great writer and thinker Lu Xun:
Those who live in China will often have occasion to hear the swear: tamade (他妈的) and others like it. I think the geographical distribution of this phrase is probably as wide as the lands upon which the Chinese have set foot; and I’m afraid the frequency of its use may not be less than that of the polite nin hao ya (您好呀). If, as some have put it, the peony is China’s “national flower”, then this has to be considered China’s “national swear” (guoma 国骂).
Quote from http://languagehat.com/tamade/
I believe that 他妈的 would be a general curse like "f--k!" (or "damn"), but not an insult , whereas 你妈的 would be a personal insult like "f--k you" or "you mother(truck)er."
Think of 他, in this context, as a generic form of "you", much like "on" in French. In other words, "one's mother" or "someone's mother" (although could also specifically be "his mother" - depends on context).
Correct me if I'm wrong, but I believe the particular insult is an euphemistic omission of the female genital organ after "的"...
It's very offensive and strange to talk to strangers or in a formal situation. It also depends on users' level of social class I think. I never use it to describe something good or when I miss somebody. Speaking of that, I never use f..k in English to talk to my friends either. I guess it depends on the people's personality. I could imagine the gangsters using 他妈的 all the time to address their buddies.
But using 他妈的 to describe a pain is really common. like if I bump my head, I would say '操,他妈的真疼'
I just witnessed a scene where the driver used this expression several times with his mistress, although I am a foreigner I thought it was very rude. I would never allow my driver to use the F word with me. They were discussing because the lady wanted him to accompany her to the school door, but he could not because the road is closed at peak hours. So he was right but very rude.
First, it is never considered as polite. It can be offensive depending on how you use it.
When used alone, it is not offensive. It is usually just expressing anger.
他妈的，好疼！ （just for pain relief） 他妈的，真热！ （just complaining） 他妈的！ (What happened is not important, we just know the person is in anger)
Used without pointing to a person
When not pointing to someone, it is not offensive.
这题谁他妈会啊？ （just complaining. 谁 is not anyone in specific, so not directional, so not offensive） 真他妈热！ （just complaining） 我他妈当场就跪了 (sort of complaining, more expressing helplessness. 我 is in the front, it is not pointing to anyone else, so not offensive)
Used with pointing to a person
It is very offensive.
你他妈有完没完 （你 is in front of tama, which is very offensive to the listener）
Soften the curse
Sometimes people use 喵 instead of 妈 to reduce the amount of offensiveness. 喵 is "meow" the cat sound.
喵了个咪 （dog my cats, expressing anger, but softer way） 你他喵的在不在听我说话 （compalaining, but softer way）
I have to disagree with the accepted answer. There is quite a bit of regional variation (some regions are reputed for foul wording), but in general 他妈的 is considered quite a bit less offensive than the f-word. IMO, it's closer to "damn" in English. "你他妈的" is much more offensive, but not nearly as offensive as that three-character word which I would not write down here (the latter is closer to "f-you", IMO).
So, yes, it is a curse word, but people tend to use 他妈的 or variants a lot when they do get angry or frustrated, and it's so common that it would barely get anyone to raise an eyebrow.