In the music man the first song on the train you can find definitions for all words like demijohn hogshead and noggin but what is a frikkin?

Answer 1

Firstly, it's not a frikkin it's a "firkin" and, according to the definition on the script, it's "a small wooden barrel or covered vessel; used for butter, lard, etc. Also any of several British units of capacity, usually equal to about 1/4 of a barrel or nine gallons." so basically it's a large, barrel-like container.