I'm looking for a book, or any other source, which lists words that are morphologically related, like this:
imagine verb imagination noun imaginative adjective
Or this:
medic noun medicine noun medical adjective medicinal adjective
And also this kind of relationship:
head noun ahead adverb, adjective
Dictionaries will give you only partial information, and in a very inconvenient way.
For example, if you look at the definition of imagination, the words imagine and imaginative are not mentioned there, nor any reference to them. I've checked several dictionaries, and you may be lucky with other ones, but I have not found one which lists all the relevant information in a straightforward manner.
Etymology dictionary is also not suitable for this task. It doesn't give you all the relevant forms of the word, and it does give historical information which is not relevant here.
Best Answer
Word by letter
Type the beginning of a word and just see how many results are churned out.
Your Dictionary
Has a more traditional approach but its resources are reliable; medic
Wordnet Click on any link and all will be revealed. Pretty amazing stuff, I say so myself.
medicine
Word Info has a box with the suffixes and the root word of imagination. Click on imag and imagi and a new page will open with a fair list of derivatives. imaginative
(list of definitions)
(list of definitions)