First class and Superlative

First class noun - Mail that includes letters and postcards and packages sealed against inspection.

Superlative and first class are semantically related. in excellent topic. In some cases you can use "Superlative" instead an adjective phrase "First class", when it comes to topics like superior, highest quality, most excellent.

Superlative adjective - Of the very best kind.

First class and superlative are semantically related. You can use "First class" instead an adjective "Superlative".

Nearby Word: superlatively