imperative

1 forcing one's compliance or participation by or as if by law reporting signs of physical abuse is now an imperative duty for hospital and school personnel Synonyms compulsory, forced, mandatory, incumbent, involuntary, necessary, nonelective, obligatory, peremptory, requiredRelated Words all-important, essential, indispensable, needed, requisite; insistent, persistent, pressing, urgent; demanded, enforced; coerciveNear Antonyms chosen, discretionary; dispensable, unnecessary, unneeded, unwanted; inconsequential, insignificant, nonessential, unimportantAntonyms elective, optional, voluntary

2 impossible to do without proper equipment is imperative for the success of this chemical experiment Synonyms all-important, critical, essential, indispensable, integral, must-have, necessary, necessitous, needed, needful, required, requisite, vitalRelated Words prerequisite; compulsory, mandatory, nonelective, obligatory; consequential, crucial, important, major, material, meaningful, momentous, significant, substantial, weighty; basic, central, fundamental, key, organic; insistent, persistent, pressing, urgentNear Antonyms undesired, unwanted; inconsequential, insignificant, unimportant; excess, external, extra, extraneous, superfluous, surplusAntonyms dispensable, inessential, needless, nonessential, unessential, unnecessary, unneeded

3 needing immediate attention an imperative need for medical supplies in the earthquake-ravaged country Synonyms burning, clamant, compelling, critical, crying, dire, emergent, exigent, acute, imperious, importunate, instant, necessitous, pressing, urgentRelated Words demanding, extreme, immediate, insistent, intense, overriding; crucial, desperate, grave, life-and-death (also life-or-death), serious, severe, vital; dangerous, explosive, hazardous, perilous, precarious, unstableNear Antonyms incidental, low-pressure, minor, negligible, trivial, unimportant; nonthreatening, safe, stableAntonyms noncritical, nonurgent