Opportunist

Opportunist, name given to a politician whose policy it is to take advantage of, or be guided by, circumstances.

Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)

Oporto * Optimism
[wait for the fun]
Opera
Opera Bouffe
Ophelia
Ophicleide
Ophir
Ophites
Opie, John
Opinicus
Opitz, Martin von
Oporto
Opportunist
Optimism
Opus Operatum
Oran
Orange River
Orange River Colony
Orangemen
Oratorio
Oratory, Congregation of the
Orcagna
Orchardson, William Quiller