Obstinate
Orderly
Old fashioned
Opportunistic
Odd
Do you mean what Norse god starts with o? Odin is a Norse go that starts with O.
Youthful.
Amirable. Amazing. Astounding.
Omoo is the Melville tale that starts with O.
A machine that starts with O is an oscillating fan.
an octopus is a simple machine that starts with a o
Oman is the only country that starts with O.
No planet so far known, begin with the letter O.
Onion and Oriental radish are vegetables. They begin with the letter o.
O
Lions can be described as overpowering. The word starts with the letter o.
o