The following are the only words containing the adjacent pair of letters "UU". Words marked # are only good in SOWPODS2003, words marked $ are only good in OTCDWL2+LL1.
carduus(-es)# continuum(-s) duumvir(-i,-s) duumviral# duumvirate(-s) individuum# lituus(-es)# menstruum(-s) mutuum(-s)# muumuu(-s)$ paramenstruum(-s)# residuum residuums$ squush(-ed,-es,-ing)$ triduum(-s) ultravacuum(-s)$ vacuum(-ed,-ing,-s) weltanschauung(-en,-s)$