Prefixes un- and in- are two similar prefixes which, if attached to a word, will create an opposite meaning.
Examples of words with prefix un-:
Undo, meaning the opposite of do
Unsaid, meaning not said
Unnecessary, meaning not necessary
Unwanted, meaning not wanted
And many more.
Examples of words with prefix in-:
Inactive, meaning not active
Incompetent, meaning not competent
Indirect, meaning not direct
Indefinite, meaning not definite
And so forth.
You can find many more examples in the dictionary. So, our main question will be when we use either prefix. Why do we say ‘unfinished’ instead of ‘infinished?’ Why do we use ‘incomplete’ instead of ‘uncomplete?’ Besides, those two words have similar meaning, too.
Many scholars argue that words that have English/Germanic root will go with prefix un- and words that have Latin root will go with prefix in-. To ensure which prefix we should use between the two, I think we will have to read often to increase our vocabulary.
Other prefixes that are the variations of prefix in- are prefixes im- (e.g., ‘impartial,’ meaning not partial), ir- (e.g., ‘irresistible’), and il- (e.g., ‘illegal’).
Now, can you give me more examples of words with prefixes un- and in-?
@Marco_20July: Uncertain, meaning not certain
Unsure, meaning not sure