words that have the prefix ir
The prefix, however, is actually in-, such as incapable. You change the n depending on â¦ the word. Words that begin with l use the prefix il- (e.g. illegal), words that begin with r use the prefix ir- (e.g. irresponsible) and words that begin with m or p use the prefix im- (e.g. immature or implausible). You use the prefix in-in all other cases. 10 people found this useful.