First class and Fab

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

Fab and first class are semantically related. in prime topic. In some cases you can use "Fab" instead an adjective phrase "First class", when it comes to topics like best, impressive, excellent, grand.

Fab adjective - Of the very best kind.

First class and fab are semantically related. Sometimes you can use "First class" instead an adjective "Fab".