na-adjective
Describes something happening without delay, often with a sense of urgency. Used as a な-adjective.
速急な対応が必要だ。
An immediate response is necessary.
彼は速急に行動した。
He acted quickly.
Compound of 速 (speed) and 急 (urgency). The exact historical derivation is uncertain; it is a less common synonym of 早急.