· obedient
· obnoxious
· obscene
· observant
· odd
· oddball
· offensive
· old-fashioned
· optimistic
· outgoing
· outrageous
· outstanding
· overbearing
· overconfident
old
optimistic
Lions can be described as overpowering. The word starts with the letter o.
outstanding
Bombs are overpowering and destructive. The adjective begins with the letter O.
obedientobjectiveobservantopenopen-mindedoptimisticorganizedoriginaloutgoingoutspokenoutstanding
other
· outstanding
who
You don't. The letter O is a letter, not a word. The word "oh" is a word but it does not stand for the letter O.
Outback
Outstanding, optimistic and outgoing are positive descriptive words. They begin with the letter o.