According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 19 words with the pattern OU-ST----. That is, nine letter words with 1st letter O and 2nd letter U and 4th letter S and 5th letter T. In alphabetical order, they are:
ouistitis
outstands
outstared
outstares
outstarts
outstated
outstates
outstayed
outsteers
outstrain
outstride
outstrike
outstrips
outstrive
outstrode
outstroke
outstrove
outstruck
outstunts