necessary
US /ˈnes.ə.ser.i/
UK /ˈnes.ə.ser.i/

1.
required to be done, achieved, or present; essential
:
•
It is necessary to obtain a visa before traveling to that country.
•
A good night's sleep is necessary for your health.
1.
something that is necessary
:
•
We've done all the necessary.
•
Take only what is necessary.