First class and Prizewinning

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

Prizewinning and first class are semantically related. In some cases you can use "Prizewinning" instead an adjective phrase "First class".

Prizewinning adjective - Of the very best kind.

First class and prizewinning are semantically related. Sometimes you can use "First class" instead an adjective "Prizewinning".