What is the best definition for the word impending?

The word "impending" refers to something that is about to happen, often conveying a sense of immediacy or urgency. Therefore, "approaching" aligns perfectly with this definition, as it suggests that an event or situation is drawing near and will occur soon. This term is frequently used in context to describe impending weather events, deadlines, or any situation that is on the verge of happening. It captures the anticipation and expectation associated with events that are imminent, making it the most suitable choice among the options provided.