応急
おうきゅう · oukyuu · JLPT N1 · noun
emergency
🚑 応 (respond) + 急 (urgent) = respond to something urgent: emergency
応 means respond or answer, and 急 means urgent or sudden. Together, 応急 is a response to an urgent need, such as 応急処置 (first aid) or 応急措置 (emergency measures).
急 — heart radical 心 + 及 (reach)
A semantic-phonetic compound: the heart radical 心 supplies the meaning (an emotional state) while 及 ('to reach, catch up') gives the sound. Originally it depicted a racing, anxious heart — hence the modern senses 'urgent,' 'hurried,' and 'impatient.'