Of course
Certainly, definitely, naturally."Of course you can use my car if you want to."
Of benefit to (someone)
To be good for someone, to be a benefit to someone.Another meeting to solve the problem is of no benefit to myself so I will not attend.
Of all things
Imagine that!."Of all things," the woman said when the post office employee told her that her package was too large for delivery.
Of all the nerve
How shocking.Of all the nerve for my friend to ask me for more money when she never repaid me what she had already borrowed.
Of age
To be fully developed, to be mature.Rapid transportation came of age when the first jets were built.
Of age
To be old enough to be allowed to do something (vote or drink etc.).When my cousin came of age we had a big party to celebrate.
Odor of sanctity
An atmosphere of excessive holiness or piety.There was an odor of sanctity in the chambers of the judge at the courthouse.
Odds and ends
A variety of small items (sometimes remnants of something else).We made games for the children from odds and ends that we have at our house.
An oddball
A person who does not act like other people.The man is an oddball and nobody likes to work with him.
(the) odd (something)
An extra or spare something, one or two of something.We saw the odd animal on our hike in the mountains.