I. noun
Synonyms: essential 2, condition, must, necessity, precondition, requirement, requisite, sine qua non
II. adjective
Synonyms: essential 4, imperative, indispensable, necessary, necessitous
I. noun
Synonyms: essential 2, condition, must, necessity, precondition, requirement, requisite, sine qua non
II. adjective
Synonyms: essential 4, imperative, indispensable, necessary, necessitous
Merriam Webster. Collegiate thesaurus English vocabulary. Английский энциклопедический словарь тезаурус. 2003