1. urgency Necessity is the quality of being necessary, or the quality of that which can not but be, become, or be true, or be accepted as true. Need and want always imply a lack; necessity may be used Synonyms: necessity, compulsion, fatality, requisite, destiny, fate, sine qua non, emergency, indispensability, unavoidableness, essential, indispensableness, urgency, exigency, need, want, extremity, requirement Antonyms: choice, doubt, dubiousness, freedom, possibility, contingency, doubtfulness, fortuity, option, uncertainty
Synonyms for urgency 
