Old English wosig "juicy, moist;" see ooze (v.) + -y (2). Original sense now obsolete; meaning "containing or resembling fine soft mud; having the consistency of wet mud or slime" is from 1560s. Related: Ooziness.
oomph
-oon
oops
Oort cloud
ooze
oozy
op-
*op-
op. cit.
opacity
opafication