Negative or opposite:
* inaccurate: not accurate
* inactive: not active
* incapable: not capable
* incomplete: not complete
* incorrect: not correct
* indefinite: not definite
* inefficient: not efficient
* inelastic: not elastic
* ineligible: not eligible
* infamous: not famous (but known for bad reasons)
* inhuman: not human
* injustice: the opposite of justice
* invisible: not visible
Into or within:
* incorporate: to include something within something else
* incursion: a sudden attack into enemy territory
* indent: to make a space within a line of text
* infiltrate: to enter secretly into a place or organization
* ingest: to take something into the body
Other:
* incessant: continuing without stopping
* indeed: truly, in fact
* independent: not relying on others
* indigenous: originating in a particular place
* induce: to cause something to happen
* infer: to conclude something based on evidence
* inflate: to make something larger by filling it with air or gas
* influence: to have an effect on something
This is just a small sample. There are many other words that begin with "in-".
Remember that the meaning of "in-" can vary depending on the word. Sometimes it means "not", other times it means "into", and sometimes it has a more specific meaning. It's important to look at the whole word and consider its context to understand the meaning of the prefix.