Green’s Dictionary of Slang

grout n.

In phrases

on the grout (adj.)

(Aus.) in trouble, out of favour.

1919

Tweed Dly (Murwillumbah, NSW) 17 May 7/4: But I’ve come a regimental; I have lobbed; I’m down and out. / I have landed good and clever; I have got the right about, / And I’ve lost all faith in women, and I’m out upon the grout, / Since that snoozer with a dial like a meat-axe cut me out.