There are so many useful terms now falling foul of the forums "common words" list, that the search is becoming less and less useful.
Would it be possible to lower the common word threshold, or disable it completely? It is easily done in the phpBBS admin page (GENERAL/Server configuration/Search settings/Common word threshold). Note that after making any such change, you need to delete the search index and recreate it again.
I run my own phpBBS forum with a zero common word threshold, and am not aware of any major issues with disabling it in this way.