What does indicative, subjunctive and imperative mean?

See explanation.

Those terms are moods of :

Indicative sentence is a sentence which informs about some facts. Example:

John did not go to work because he was ill.

Subjunctive sentence is a sentence telling about assumptions and hypothetical situations. Example:

If I won in a lottery, I would buy a new car.

Imperative sentence means giving someone orders or commands: Example:

Do not lie to me.