Except

Using the Except(string) function, you can remove a character, a set of characters or a range of characters from the search pattern.

The following will produce the following regular expression [a-zA-Z-[a-e]]*

var result = se
    .Letters
    .Except("a-e")
    .Generate();

ExceptWord(string) removes a whole word from the matches, but can only be combined with whole word search. The following will match ponys and unicorns, but not ponys and rainbows.

var result = se
    .Letters
    .ExceptWord("rainbow")
    .Generate();