1.
suddenly, in haste, on short notice, at the last minute
Doing something hastily or without advance planning, typically because of unexpected circumstances. Implies urgency and a change from the original plan.
Usage
急遽 implies that an action was taken hastily due to unforeseen circumstances. It differs from 突然 (suddenly), which simply describes something happening without warning. 急遽 emphasizes the reactive, last-minute nature of a decision or action.
Common in news reporting and business contexts. Slightly more formal than 急に.