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 don't mean someone who is totally mentally challenged. I am referring to ones whose mental growth is not proportional to the physical.

share|improve this question

closed as not constructive by FumbleFingers, coleopterist, MετάEd, Mark Beadles, Carlo_R. Nov 8 '12 at 21:13

As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance.If this question can be reworded to fit the rules in the help center, please edit the question.

So, are we talking about a six-foot man with the mind of a five-year old or not? If we are, in what sense is he not "retarded/mentally challenged"? If we're not, exactly how much of a size/brainpower mismatch are we talking about here? I am asking in all seriousness, but I think the question is inevitably going to be Not Constructive. – FumbleFingers Nov 8 '12 at 18:29
@FumbleFingers , am referring to someone, who is not ready to consider himself fit to face the real world. And so stuck in the burrow. So - he had to stay in the shadow of his family. But - I want to use a polite sense, as he is THE GUY of my plot ;) – satya Nov 8 '12 at 18:46
In that case it's very much Not Constructive. You obviously have your own understanding of what "mental growth" (or lack of it) actually means - most people aren't particularly likely to think of it as specifically meaning having the qualities of self-confidence and independence needed to contemplate life outside one's birth family. – FumbleFingers Nov 8 '12 at 18:53
@FumbleFingers, consider - I want to revamp my definition to someone who could not grasp well, be it education or the reality of life. What word would you recommend ? Is "Intellectually challenged" a fit word ? – satya Nov 8 '12 at 18:56
A fairly common idiom would be to say that someone is "25 going on 16", for example, for a person who is physically 25 but has the emotional development of a 16-year-old. (It's an inversion of the also-popular "13 going on 30"-style phrasing, said of someone who is mature or sophisticated beyond their years.) – Hellion Nov 8 '12 at 19:23

I think immature (as a general description of the individual, as opposed to being applied to any specific action of theirs) adequately describes the classic situation of someone who should be moving out on their own, but doesn't feel--or doesn't show evidence of being--ready to take the big step.

share|improve this answer

Mentally retarded was originally the term for this, but euphemism creep has turned that into an unacceptable insult.

Having a development disorder is commonly used now.

share|improve this answer
Thanks, I have learnt the word euphemism. – satya Nov 8 '12 at 18:50
Autism - Development disorder, suits my case. Thanks a lot for the help. – satya Nov 9 '12 at 5:29

You might be looking for manchild. This is more of a derogatory term, however.

A somewhat obscure one, borrowed from Japanese, is hikikomori, but this is perhaps more extreme than what you wanted.

Regarding staying home, homebody could be it.

share|improve this answer

What about something like the following?

 He has the body of an adult and the mind of a child. 

I do not think you can be more succinct and avoid the connotations of a medical condition.

share|improve this answer

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