I think they are called stop words, words that often trigger PSA's instead of showing ads e.g. expire. Can these lead to an adsense account ban, or non-showing of ads is as far as it will go?
Only if your whole site is one big stop word (i.e. you're not getting any ads at all anywhere on the site) in which case you've violated the TOS by putting ads on a site that isn't allowed by Google.
Is there a definitive list of these adsense stop words? If one HAD to use such words would it be advisable to display them via a javascript document.write?
If there are so many stop words on your site that you are getting nothing but PSAs all over the place, then there is a VERY GOOD CHANCE your whole site is in violation of the Adsense TOS, in which case maybe you shouldn't put Adsense on it in the first place. But if one or two (or even a dozen) pages have stop words that are producing PSAs, leave it alone. A dozen pages with PSAs isn't going to have any noticable impact on your earnings unless your entire site consists of just 12 pages to begin with.