Some languages allow the formation of longer word by composition using hyphens. Moreover, proper names may contain hyphens. Therefore we look for the most frequent words containing 1, 2, 3 or 4 hyphens.
Usually we find interesting words. But in the case of poor preprocessing there may be unexpected strings resulting from hyphenation etc. Words ending with an hyphen are usually not welcome, too.
For three hyphens:
select w_id-100,freq, word from words where word like "%-%-%-%" limit 10;
3.12.2 Multiwords
3.12.3 (Multi-)Words with dots
3.12.4 Words containing special characters