Tafsir of An-Najm 53:57

"The Inevitable has approached" means the Hour, which is described as being near in more than one verse of the Quran, has drawn near.

The alif and lam (the definite article) in "al-Azifah" (The Inevitable) are for specifying a particular entity (lil-'ahd), not for denoting a generic category (lil-jins).

It has been said that "al-Azifah" is used here as a proper noun that has become synonymous with the Hour. It has also been said that there is no harm in intending the generic category, and the description of something near as being "near" is for the purpose of intensification.