although it's written as "coosie" in the notes

.... and I wondered at that when the album came out. The Scots Dialect Dictionary (Waverley Books ISBN 1-902407-09-01) has the following definitions:-

Couthy (Couthie) - kind, pleasant, agreeable, affable
Coosie - a challenge to a feat of daring, dexterity or difficulty

So it is pretty obvious thay 'couthy' fits in with the meaning of the song.
I heard Lizzie sing the song many times live and it always sounded like 'couthy' to me. I only saw the notes after the album had been released so it was a bit pointless to point it out then. Anyway, the transcriptions were by a great friend, Danny Stradling, and I had no wish to appear nit-picking with her.