Negative Prefixes

[albertino]

when we add a prefix such as in- or un- or dis-,im-, il-, non, ir- etc. to the beginning of adjectives, adverbs and verbs giving them the opposite meaning, are there any hard and fast rules governing all these? For example,
before "r" one has to use "ir" like irreparable;
before "l",use "il" like illogical;
before "t", use "dis" like distrust;
before "c, b or s" use "un or in" like uncomfortable/unbelievable and incomplete/incredible/insanity;
before "p", use "im" like impossible;
before "h or f", use "un" like unhappy/unfettered;
before a noun, use "non" like non-smoker, etc.

Thanks.:roll:

 

[Tdol]

They're not so much hard and fast rules as tendencies, and there are usually exceptions. We have irregular, but unreliable.

 

[albertino]

They're not so much hard and fast rules as tendencies, and there are usually exceptions. We have irregular, but unreliable.

So, Where can I find the negative prefixes of words if need be?
A dictionary? (seldom helps), an online source, if any, but where?

 

[Anglika]

Using this: Thesaurus.com look up your head word [regular] and you will find the antonym(s).

 

[albertino]

Using this: Thesaurus.com look up your head word [regular] and you will find the antonym(s).

Thank you very much. Excellent:up: .

 

[BobK]

Afterword:

I've made a start on a list, in the hope of finding something like a pattern. But in making the list I had to make lots of decisions about what was admissible and what was inadmissible (or in some cases unadmissible - both words exist): what words were too obscure to concern students; what should I do with negatives that had no positive (like 'disgruntled' and 'uncouth'); what should I do with words with a clearly negative sense like 'dethrone' of which the positive has its own prefix ('enthrone'). So I've concluded that Anglika's answer (no. 4) is the best approach, and the most accurate general answer was Tdol's (no. 2)

The nearest thing to a pattern I came across was that im- in- il- and ir- are a family. If a word can take one of these prefixes it can't take another; the negative is il- if the initial letter of the positive is l, im- if the initial is bilabial (m b or p), ir- if the initial is r, and otherwise in- - but even this has an exception ("noble/ignoble").

I attach the work so far (which I'm not sure is worth pursuing). It's certainly not exhaustive, and all it does is underline that Thesaurus.com is the best resource.

:-(

b

PS The original file is in XLS format; this one has no comments, and the tabs don't work - so it's not very pretty.