Dire and Split-second

Dire adjective - Being or showing a sign of evil or calamity to come.

Split-second and dire are semantically related In some cases you can use "Split-second" instead an adjective "Dire".

Split-second adjective - Done or occurring without any noticeable lapse in time.

Dire and split-second are semantically related in immediate topic. Sometimes you can use "Dire" instead an adjective phrase "Split-second".