Deadline and D-day

Deadline noun - The point in time at which something must be completed.

D-day and deadline are semantically related In some cases you can use "D-day" instead a noun "Deadline".

D-day noun - Date of the Allied landing in France, World War II.

Deadline and D-day are semantically related in time limit topic. Sometimes you can use "Deadline" instead a noun phrase "D-day", if it concerns topics such as moment of truth.