First class and Skillful

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

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

Skillful adjective - Accomplished with trained ability.

First class and skillful are semantically related. Sometimes you can use "First class" instead an adjective "Skillful".