Some five letter words with O as the second and third letter are:
Examples of five letter words that end in "o" are:AlamoaudiobanjobingobongobravoburrocameocargoCongocuriodingodittofolioforgogeckoguanogumbohelloigloojumbokazoolassolimbolottomangomatzomomboMongomottonachooutdopatiopestophotopianopolioradioratiorhinorodeoRomeotabootangotempotorsovideoYahoo
gusto
hobo
Bongo
AlamoAmigoAminoAudio
natio
Some four letter words that end with "o" are:zerohaloherohobointojudokiloalsoaltoautoechomemoontopolosilosolotacotarotrioundoveto
Five letter words that start and end with letter O are outdo and outgo.
tornadotorpedo
Ratio
Cameo
According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 1 words with the pattern -O-OO. That is, five letter words with 2nd letter O and 4th letter O and 5th letter O. In alphabetical order, they are: potoo