What does 'for' mean in 'We are done for'?
There is an English expression do for, which means to kill, to execute, to ruin, to defeat etc. and this expression seems to always be used in passive voice: e.g.) We are done for.
I understand this is like an idiom, but why is the preposition for used? Most prepositions have so many meanings to them, and I would like to know what for in this case means.
edit: https://dictionary.cambridge.org/us/dictionary/english/for https://en.oxforddictionaries.com/definition/for
In the definitions of the above links, which for do you all think the for in done for is the closest to?
edit 2: I don't think the for is dangling, but I just want to know why for is used. Like, for normally means purpose, cause, or to be given, etc. But the for in question means quite opposite.
Solution 1:
"For" at this point doesn't seem to have any meaning here, although it does add a little emphasis.
Specifically, it looks to me like "done for" could be actually a variation of the even older, now-obsolete verb "fordo".
The earliest example in the OED for "done for" is from a1500:
By thre skyllis may hit come to Why hit [sc. a stillborn child] is don for [Lansd. fordone] alsoo.
Sidrak & Bokkus (Laud)
"[Lansd. fordone]" means that in another manuscript they used "fordone" instead of "don[e] for". (Unfortunately I haven't been able to access either version.)
If you look at this free definition for "fordo" (for Middle English, but still applicable), you'll see it is essentially a synonym for "done for". "Fordo" is ancient (first attested in English in the year c900) and apparently derives from "Proto-Germanic *fardōną, *fradōną (“to ruin, destroy”)".
According to the OED, the "for" prefix in "fordo" means:
Implying destructive, painful, or prejudicial effect, as in fordeem, fordo
It's worth mentioning that the now-obsolete word "fordeem" is a synonym because it means "to ruin or destroy", although it also means "to condemn". There are other obsolete words that also have this "for" meaning destruction prefix but I can't think of any current ones. Of course there are plenty of current verbs with other senses of the same "for" prefix: forgive, forget, forbid, etc.
Solution 2:
tl;dr - It's not the word you think it is
Short answer: the "for" isn't a preposition, it's part of the verb "to do for", it doesn't have any meaning on its own, and the reason why that word and not another are lost in the mists of time - if there ever was a reason.
Phrasal verbs
"To do for" is an example of what's known as a phrasal verb in English. The verb is to do for, and it's transitive (i.e., it takes a subject, so you have to say "to do for (object)"). This can look confusing if you try to analyse it as the construction "to do (X) for (Y)", but in that case the verb is simply "do", and "for" is acting in its normal role as preposition.
The closest synonym for "to do for" is to doom, although many of the common uses can also carry the meaning of "to kill". "To do for" is quite informal, though - you won't see this in a coroner's report, but you will often hear people on the street using it (e.g. "It was the drink that did for him in the end", or "He did for my shin with that last tackle!").
As you note, "We are done for" is simply the passive-voice version of the active sentence "(someone) has done for us", meaning that someone has doomed us to a fate, although that fate does not have to be death. It's almost a stock-phrase, and it's slightly comedic: this phrase is often uttered by villains in British comedy writing - there it is best translated as "all is lost, and we will be caught and imprisoned".
"Do for" is used in its active sense, but very rarely in American English. I have heard British speakers saying things like "I did for my leg last night" meaning that they've injured themselves, but it's very much informal, and it may be regional (North of England rather than South).
The bits don't mean anything on their own
Some advice: do not try to look for some kind of deeper meaning behind the two parts of this kind of verb. Some make sense ("take in", "drop off", "run out"), but others don't really ("do in", "let on", "give up", "turn up"). Just accept that in English, there are some verbs that are made up of a "verby" word and a "prepositiony" word that act together to create a completely new, and usually idiomatic, meaning.
( This isn't just English, by the way. German has many such idiomatic phrasal verbs such as umbringen. That one looks like it should mean "bring around", from "um" and "bringen", but it actually means "to kill" - however, the sentence "ich bringe die Kinder um 08:00" doesn't mean you're planning a murder!)
Here are some other common phrasal verbs of the same type as "do for":
- I give in : I admit defeat
- She gave out about... : (first meaning) She complained about...
- The bearing gave out : (second meaning) The bearing failed
- I give up : I quit
- I did in my knee : (informal) I damaged my knee
- I did up the room : I decorated the room
- She turned up today : she appeared today
- She turned down the invitation : she declined the invitation
- She had a grey dress on : She wore a grey dress
My personal experience (I speak British English, but work extensively with Americans) would suggest that there are more of these verbs in regular use in British English than American, but they're a common feature of English, and they're not something you can avoid.
Solution 3:
According to Green’s Dictionary of Slang done for is the adjectival form of the phrasal verb do (a bad turn) for meaning to injure, kill. The preposition for would derive from the verbal form.
Done for adj.
(do for v./ext. of done adj.)
1821: without a chance, hopeless, defeated, lost, abandoned, ‘finished’.
- 1843 [UK] ‘Bill Truck’ Man o’ War’s Man - 112: He’s done for now,
Do for verb:
[Do v.1 (1)/abbr. SE phr. do a bad turn for
to beat up, to injure, to murder.
- 1751 [UK] Fielding Amelia II 70: He said something, too, about my master [...] he said he would do for him, I am sure he said that; and other wicked, bad words, too.