requisite, imperative, essential; see necessary 1.
"required." YourDictionary, n.d. Web. 22 June 2018. <http://thesaurus.yourdictionary.com/required>.
required. (n.d.). Retrieved June 22nd, 2018, from http://thesaurus.yourdictionary.com/required
Incapable of being dispensed with:
Imposed on one by authority, command, or convention:
Do you use YourDictionary every day? If not, remember that it is never to late to do so!
Let us be there for you: