have³ S1 W3 verb, have to do something (also have got to do something especially British English)

1. if you have to do something, you must do it because it is necessary or because someone makes you do it:
We don’t have to rush – there’s plenty of time.
I hate having to get up early in the morning.
If you earn more than £5,000, you will have to pay tax.
I’ve got to be at the hospital at 4 o'clock.
It’ll have to be on a Sunday. I’ll be working every other day.

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In writing, people often prefer to say someone is forced to do something or is obliged to do something, as these sound more formal than have to do something:
■ They had to pay tax on the full amount. ➔ They were obliged to pay tax on the full amount.
■ | Many businesses have had to close. ➔ Many businesses have been forced to close.

2. used to say that it is important that something happens, or that something must happen if something else is to happen:
There has to be an end to the violence.
You’ve got to believe me!
There will have to be a complete ceasefire before the Government will agree to talks.
You have to be good to succeed in this game.

3. used to tell someone how to do something:
First of all you have to mix the flour and the butter.

4. used to say that you are sure that something will happen or something is true:
House prices have to go up sooner or later.
This has to be a mistake.
You have got to be joking!
No one else could have done it – it had to be Neville.

5. used to suggest that someone should do something because you think it would be enjoyable or useful:
You’ll have to come and meet my wife some time.

6. spoken used when something annoying happens in a way that things always seem to happen:
Of course it had to happen today, when all the shops are shut.

7. spoken used to say that only one thing or person is good enough or right for someone:
For Francesca it has to be the Ritz – nowhere else will do.

8. do you have to do something? spoken used to ask someone to stop doing something that annoys you:
Lieutenant, do you have to keep repeating everything I’ve just said?

9. I have to say/admit/confess spoken used to show that you are making an honest statement even though it may be embarrassing for you:
I have to say I don’t know the first thing about computers.
⇒ must¹

[TahlilGaran] Dictionary of Contemporary English ▲

must do something used when saying that it is very important that someone does something, because someone in authority or a rule says this, or because of the situation:
You must be home by midnight.
He must not smoke in here.
I must remember to call her.
have to do something to need to do something because it is necessary or important:
I have to go home early.
She has to talk to him first.
be obliged to do something especially British English to have to do something, because of a legal, professional, or social rule:
Members of parliament are obliged to declare all their financial interests.
be required to do something (also be obliged to do something especially American English) formal to have to do something – used especially in written notices and official documents:
New students are required to register with a doctor.
have an obligation to do something (also be under an obligated to do something) to have to do something because it is the duty of someone in your position to do it, or because you have officially agreed to do it:
The landlord is under an obligation to keep the building in good repair.
be forced/compelled to do something to have to do something that you do not want to do, because you are in a situation that makes it impossible to avoid:
She was forced to retire early due to ill health.

[TahlilGaran] English Thesaurus ▲

have to do something
be obliged or forced to do something
I have to leave at 4:00 or I will be late for my appointment.

[TahlilGaran] English Idioms Dictionary ▲