Of no avail
(Of no use)–My attempts to reform my brother was of no avail.
Of one’s own accord
(Of one’s own free will) – He has resigned his job of his own accord.
Of the first water
(Of the highest quality) – She was a beauty of the first water; He is a television journalist of the first thing about cars.
Off and on
(Irregularly; from time to time) – Waqqar comes to my house off and on.
On the eve of
(The day before; just before) – The unwilling bride escaped from her house on the eve of her wedding.
On the horns of a dilemma
(In a critical situation) – He was on the horns of a dilemma; if he returned into the house he must die in the flames, and if he came out the soldiers would shoot him dead.
Once for all
(Finally) – My father has told me once for all, that if I fail in my class, he will not allow me to continue to my studies.
Open secret
(supposedly secret fact known to many people) – It’s an open secret that the Chief Minister is about to resign.
Out and out
(Completely) – He is out and out a rascal.
Out of bounds
(Outside the permitted area or limits) – The cinema was out of bounds for the boys from the local boarding school.
Out of date
(Very old; obsolete) – My father wears out of date items of dress.
Out of one’s mind
(Mad) – He wants to climb the Everest without the oxygen mask; he must be out of his mind.
Out of order
(Not in a working condition) – Our ceiling fan is out of order.
Out of sorts
(Unwell) – I am out of sorts today and intend staying at home.
Out of stock
(Not available for sale) – Our physics textbook is out of stock in all the bookshops in the city.
Out of the frying pan into the fire
(From a bad position into worse) – I changed my job because it was not lucrative but soon I realised that I had jumped out of the frying pan into the fire.
Out of the question
(Impossible, not to be discussed at all) – We can’t go out in this weather. It is out of the question.
Out of the wood
(Out of difficulties) – Our defence production has improved but we are not yet out of the wood.
Over and above
(Besides) – Over and above his clerical duty, Manzoor’s father does some odd jobs to make an extra penny.
Over and over again
(Repeatedly) – Our English teacher keeps telling us over and over again that hard and honest work will always bear good fruit.
Over head and ears
(Completely) – He is over head and ears in debt.