Prefixes, how and where to use negative prefixes like un-,dis,non-,etc?

Unfortunately, there are no rules, only usage, so you'll have to use the dictionary, Praveen. Webster's Collegiate Dictionary, in addition to the more common negatives in the main listings, also includes a long list of other words with the same prefix.

Hi micawber,
Thanks for your information.
Meanwhile, do you know the reasons for their present usages like dis- in disappointment,un- in unimportant,etc.Are there any rules for their usages or just they are employed inaccordance to better pronunciation.
praveen.

There is no rule. Words with these prefixes have come about through accidents of history. The most usual is "un-", but always consult a dictionary. The following does not really answer your question, but you may find it somewhat useful anyway, especially if you're willing to work to dig some of this out of a dictionary.

Dissertation on "Negative Prefixes" in English.

"a-" is a

Hi califjim,

Excellent material.You have done a great job.
Thanks for your help.

praveen.

Are only these prefixes (a-, non-, in-, dis-, un-) negative one? What about anti-, contra-, counter-, de-, ex-, and extra-? Aren't they sometimes negative, too? Do negative prefixes have influence on pronunciation?

Hello Bozena,

Welcome to English Forums.

The prefixes you mention are not specifically negative, but carry meanings of 'opposite', 'down', 'out', 'beyond', or associated ideas depending on the specific use. The entire word formed, of course, could be negative by association, irrespective of the prefix: 'superbad'.

Prefixes of any kind may or may not influence word s

Thanks a lot, CalifJim. However, I must point out that yes, you CAN 'plane' someone.
"I planed him" means "I hit him with a plane"

You can also 'car' somebody. You can also 'glass' somebody.
"Dude! I totally glassed him!"
Means
"My friend, I would like to exclaim loudly and excitedly that I cut my friend with glass shards"

There.

This is a concept

"I planed him" means "I hit him with a plane"

You can also 'car' somebody. You can also 'glass' somebody.
"Dude! I totally glassed him!"

And you can bus someone somewhere, so I suppose you can car someone somewhere.

So in "I carred them home" you're doing a favor, but in "I carred them in the street" you probably did quite a bit of damage.

Hi, freak guy,

of course, there are very strict rules, but these rules are rooted in ancient LAtin, if You do not know Latin, then You can claim there are no rules. But if You are not educated enought, You should not state such a nonsense. There are rules as to what consonants or vowels must precede to add this or that prefix. Have you ever heard of a progressive assimilation, for example

Hi Zdenek,

This last post seems to me to be a very feeble attempt to be ill-mannered and annoying. Can't you do any better than that?

Clive