なさいdo it (said by parents, teachers)
How a parent tells a child, or a teacher a student, to do something. It is an order: firm, not rough, and not said to someone above you.
a parent
It's already late, so hurry up and go to bed.
How to form it
Verb ます-stem + なさい
食べます → 食べなさい, 読みます → 読みなさい, します → しなさい, 来ます → 来なさい.
At home and at school
Children hear it all day at home. Teachers use it when they are being firm; their everyday instructions are more often てください or ましょう.
Tidy your room right now.
a teacher
Stop what you're doing and look this way.
An older person can say it kindly to a much younger adult: a boss sending someone home, for one.
If you have a fever, go home for the day.
On tests
Test papers and worksheets often give their instructions with なさい. Nobody is being talked down to; it is how tests are written.
Choose the one that is correct.
Answer the following questions.
It isn't "please"
It sounds gentler than 座れ, but it still tells; it doesn't ask. Said to a teacher, a boss or a stranger, it treats them like a child. A request is てください.
Not said: 先生、
(Please have a seat, Professor.)
どうぞ、座ってください.
Said to a friend or a partner, it mothers them, often half in fun.
おやすみなさい, ごめんなさい
おやすみなさい (good night), お帰りなさい (welcome home) and ごめんなさい (I'm sorry) are set phrases. Nobody hears an order in them.
In casual talk: 行きな
With people you are close to, なさい shortens to な. It is lighter: a nudge, not a telling-off. After a dictionary form, な is the opposite: don't.
Close neighbours
書け・食べろN4
The bare order. Rougher: a coach, an emergency, a parent who has run out of patience.
Keep your eyes on the ball!
てごらんN3
"Try it and see": a gentle push, also said to children and juniors.
Try a little. I'm sure you'll like it.
Check yourself
1Who would say this?
早く
Choose an answer to see why.
2Which one fits?
食べる
Choose an answer to see why.
3What does this mean?
ここに
Choose an answer to see why.
More detail
Where it comes from
なさい comes from なさる, a respectful word for "do", and was once polite. The greetings keep that older sense.
More sentences
Before you leave, tidy up your desk.
I need to speak with you, so come to the teachers' room after school.
Check once more that you haven't forgotten anything.
First, calm down and take a slow, deep breath.
First, read the instructions.