n. 25B6; adjective
planning permission is necessary : OBLIGATORY, requisite, required, compulsory, mandatory, imperative, needed, de rigueur; essential, indispensable, vital.
a necessary consequence : INEVITABLE, unavoidable, inescapable, inexorable, ineluctable; predetermined, preordained.
25B6; noun (informal) could you lend me the necessary? : See money sense 1.