A word meaning left out that starts with O is omitted.
Words for something that has been left out include omitted, abandoned, lost and suppressed. Other synonyms include erased and obliterated.
Open Minded
Overtime!
object
The word starting with O that means working extra is overtime. It tends to be a word used when a person works over the expected hours. The pay is typically increased during this time.
Omitted.
Orthography
obtainable workovertime
veto
Obliterate
Origin
The Maori word for talk starting with a "k" and ending with an "o" is "kōrero."
ornate (decorated with fine detail)ostentatious (overly decorated)