English Language & Usage Stack Exchange is a question and answer site for linguists, etymologists, and serious English language enthusiasts. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I've seen the expression "to do someone in" for the first time today and from what I found, it means "to kill someone." Where does it come from?

The trailing "in" implies something following and makes the expression sound incomplete.

share|improve this question
The actual preposition "in" is arbitrary. In fact it looks like do someone up was around earlier, but that version sounds really odd to my modern ear. The earlier instances in that link are predominantly American, but my gut feeling is to agree with @Aaron that the in version sounds more Cockney than Yankee. – FumbleFingers Jul 4 '13 at 21:47
In latin, interficere (litt. "do into") means "to kill" too. – user109759 Feb 16 '15 at 9:24
up vote 5 down vote accepted

I'm sure the origin can be argued, but this almost certainly came from the east end of London.

When you say 'do him' or 'he did him' it means to beat someone up. So 'do him in' goes further.

Other common cockney phrases are 'Kick his head in' or 'punch his face in' so it only makes sense.

'In' being invasive, meaning entering inside, which is generally how you kill someone.

Coming from London myself it seems perfectly normal to to use 'in'.

share|improve this answer
+1. It was 'cockney slang' when Shaw wrote Pygmalion; I doubt whether further sleuthing would be worthwhile. – TimLymington Jul 4 '13 at 21:24
@Aaron The word 'in', with the definition you gave seems to fit, and brings more sense to the expression. I still think that it doesn't match up really well with the verb 'do' as opposed to 'kick' or 'punch', or could use some complements. (Maybe that's just because English isn't my native language.) – Kaivo Anastetiks Jul 4 '13 at 22:01
@KaivoAnastetiks You may not think " it ... match[es] up really well with the verb 'do'" - but that is the expression, and similar comments could be made about prepositional use in very many English expressions. But the only rule is that "there ain't no rules" and many uses just have to be accepted as 'that is the way it's developed', and 'that is the way it is'! – TrevorD Jul 4 '13 at 23:01
Hmm. Most of these (except for "do him" w/o the "in") sound fine in US-EN, too. This is interesting and plausible, but I'm not wholly convinced. I can't do better, but I'd like to see someone else try (or at least have a more thorough/cited version of this). – hunter2 Jul 5 '13 at 7:14

I looked up the meaning of this expression as it is part of the Eliza Doolittle conversation during the Ascot Race scene. The British 'aristocrats' don't understand the expression and ask for the meaning. Professor Higgins has to explain it.In the context of the hilarious sketch, it is clear that the expression is 100% Cockney.

share|improve this answer
Hi Marc, welcome to English Language & Usage. If you think you might use our site again (and I hope you do!), please make sure you take the tour. You might also find it useful to read the help page on How do I write a good question? – Chappo Jun 27 at 8:24
Regarding your answer, this adds detail to TimLymington's comment, but the question is 3 years old so few people will see your answer to upvote it. – Chappo Jun 27 at 8:32

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.