It would be nice to have the options to 
1) Ignore a word only for the current project
2) Ignore a word only for the current module

There are many cases where an unusual word is domain specific. Because it
is not a standard word, but appears a lot, one would like to ignore it.
However, permanently adding it to an ignore list may be undesirable since
in other domains (i.e. projects or modules) it would be considered a typo;
and may even be an otherwise common typo. An example is a purposeful
spelling alteration of a common word so it can be trademarked. For example:
Google rather than googol (meaning 10 to the 100th power).