According to SOWPODS (the combination of Scrabble dictionaries
used around the world) there are 6 words with the pattern --CKOS.
That is, six letter words with 3rd letter C and 4th letter K and
5th letter O and 6th letter S. In alphabetical order, they are:
buckos
deckos
geckos
jockos
sickos
wackos