Words, words, words...

Ever come across the phrase "low dudgeon", or "moderate dudgeon"?  No, of course not - dudgeon always has to be high.  It's an example of what is sometimes called a "stormy petrel" expression, where you get two words which always appear together - like stormy petrel.  It's like you can only shrug your shoulders, the only thing you can do with aspersions is cast them, only arms can be akimbo, and so on.  A closely associated concept is what are known as "fossil words" - archaic words which now only exist in set phrases, like "amok" which is now only found in "run amok", or "dint" as in "by dint of".  Funny language, isn't it?