I am wondering whether there are out there online English dictionaries which group words with identical roots together to simplify learning.

For example when I learn verb "subdue" it would be great to know immediately that the related noun is "subdual", and probably there is an adjective which I do not know yet.

Cambridge Dictionary does list related words together (e.g. in the case of sardonic it also let me know about sardonically) but not in all cases (e.g. in the case of purpose no mention of purposive can be found).

  • 1
    Many dictionaries will give related words, but none gives all related words. A word like purposive is not in general use; it is used in philosophical and legal discourse and in other academic contexts. For that reason you're not likely to find it among the related words for the purpose entry. But if you understand what the suffix ive does, and you understand what the word purpose means, you would probably be able to deduce the meaning of the word purposive upon encountering it.
    – TimR
    Jan 4, 2018 at 12:29
  • What @Tᴚoɯɐuo said. Moreover, the more common related word for purpose would be purposeful. But it's very difficult to list all related words. For example, using purpose, we could have purposes, unpurposeful, unpurposefully, etc. But some of those are in such limited use dictionaries don't bother to list them.
    – J.R.
    Jan 4, 2018 at 15:22
  • Isn't this called "derivative thesaurus"?
    – drabsv
    Jul 16, 2018 at 14:47
  • @drabsv Are you aware of any online or offline ones?
    – zesy
    Jul 17, 2018 at 13:52
  • @ Sergey Zykov I think sequencepublishing.com/thesage/thesage.html ?
    – drabsv
    Jul 18, 2018 at 10:51

1 Answer 1


You could try the wildcard feature on OneLook.

Typing *purpose* into OneLook's main window yields 13 common word results, but when you change the filter include all words and phrases, you'll find there are hundreds. (Even though most of these are phrases, it still underscores the impracticality of listing all variants beneath each word in a dictionary – particularly a print dictionary.)

But even OneLook's lengthy compendium is imcomplete; words can be coined as needed. I leave you this quote:

I describe a literary field organized around purposeful novels, she describes a literary field organized around didactic poetry. In both of our accounts, the literary field is profoundly altered at century's end — by what I call antipurposeful aestheticism and protomodernism and what Loeffelholz calls antididactic aestheticism. (Source)

It's better to learn how prefixes and suffixes work than to try to study a particular word's valid forms.

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