to forge, or imitate in writing; “cooper  a monniker,” to forge a signature.
“stout half-and-half,” i.e., half stout and half porter. Derived from the coopers at breweries being allowed so much stout and so much porter a day, which they take mixed.
to destroy, spoil, settle, or finish. Coopered , spoilt, “done up,” synonymous with the Americanism caved in, fallen in, ruined. The vagabonds' hieroglyph triangle pointing down, chalked by them on gate posts and houses, signifies that the place has been spoilt by too many tramps calling there.