indispensable /ˌɪndɪˈspɛnsəbəl/adjective 3noun 2forms 3 adjective3 •Absolutely necessary or requisite; that one cannot do without.An indispensable component of a heart-healthy diet. •Unbendable, that cannot be set aside or ignored.The law was moral and indispensable. — 1679 •(no longer used) Not admitting ecclesiastical dispensation; not subject to release or exemption; that cannot be allowed by bending the canonical rules. noun2 •A thing that is not dispensable; a necessity. •[in the plural] (informal, old-fashioned) Trousers. formsindispensables · more indispensable · most indispensable