Mood is the mode or manner in which the action denoted by the verb is represented. There are three moods in English:
Indicative
Imperative
Subjunctive
The imperative mood is used to express a command. Examples are given below.
Come here.
Wait here.
Go there.
Stop it.
Get lost.
Close the door.
Open your book.
Pay your dues.
Stop smoking.
It is also used to express an exhortation or a prayer or a request.
Get ready.
Take care of your health.
Be careful.
Work harder.
Keep left.
Have mercy upon us.
Give us this day our daily bread.
In all of the sentences given above, the verb is said to be in the imperative mood.
Definition of the imperative mood
A verb which expresses a command, an exhortation, a prayer or an entreaty is in the imperative mood.
Usage note
Strictly speaking, the imperative mood can only be used in the second person because the person commanded must be the person spoken to. But by using ‘let’ a similar idea can be expressed with the first and third person pronouns.
Let me go.
Let us go.
Let us wait.
Let them go.
The subject of the verb in the imperative mood (you) is not normally mentioned because it is understood.