- 1necessary (for somebody/something) (to do something) that is needed for a purpose or a reason synonym essential It may be necessary to buy a new one. It doesn't seem necessary for us to meet. Only use your car when absolutely necessary. If necessary, you can contact me at home. I'll make the necessary arrangements. Changes can easily be made where necessary. She has the qualities necessary to be a successful teacher.
- 2[only before noun] that must exist or happen and cannot be avoided synonym inevitable This is a necessary consequence of progress. Idioms
a thing that is bad or that you do not like but which you must accept for a particular reason The loss of jobs is regarded as a necessary evil in the fight against inflation.
Check pronunciation: necessary