To exclude common words (see ACP ? Search settings ? Common word threshold):
find in portal/block/wordgraph.php
FROM ' . SEARCH_WORDLIST_TABLE . ' add after
WHERE word_common <> 1

To exclude common words and words contained in search_ignore_words.php
find in portal/block/wordgraph.php
$sql ...

I just increase number of letters for words, to exclude words with les then to 5 letters.

first: hi at all :)

your advise did not work in my wordgraph. perhaps the list of words are not updated, but i tried much (not everything ;) )

so use this solution, without Nekstati exclude list firtst ...