"unconvenient" or "inconvenient"? Rules for 'un-'

[Pstein]

What is the correct negation of convenient?

"unconvenient" or "inconvenient" ?

Is there a general rule which should be used ?

Peter

[Kitosdad]

"inconvenient" ?

Sorry, don't know the rule, if any. Just know that it is.
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[Milanya]

So many negative prefixes
Author: Thomas Tsoi

In English, we can use a number of prefixes on adjectives to form their opposites. The following pairs come to mind as examples:

typical - atypical
hydrous - anhydrous
social - antisocial
honest - dishonest
legal - illegal
possible - impossible
active - inactive
regular - irregular
existent - nonexistent
kind - unkind

In most cases, these prefixes are not interchangeable, so we do not have *unlegal or *apossible, for instance. Of course, fluent speakers have no problem in using the right prefix for the right word, as more than often, the negative adjectives are learned word by word.
Having recognized that some of the prefixes are in fact no more than variations of the same prefix, our list of negative prefixes can be reduced to the following:

a- (an-)
anti-
dis-
in- (il-, im-, ir-)
non-
un-
http://www.linglish.net/2008/09/15/so-many-negative-prefixes/
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con·text - The part of a text or statement that surrounds a particular word or passage and determines its meaning.