noun, noun which may take the genitive case particle 'no', adverb
as soon as possible; ASAP; with the utmost urgency
Stronger than 至急; used in business or formal requests to demand immediate action. Often used adverbially with に or as a noun with の.
Please reply as soon as possible.
This is a matter of the utmost urgency.
We will handle it with the utmost urgency.
Compound of 大 (dai, 'great') + 至急 (shikyū, 'urgent'). The prefix 大 intensifies the urgency, making it a stronger version of 至急.