Green’s Dictionary of Slang

willow adj.

[SE willowy, slim]

(UK Und.) poor, of no reputation.

[UK]B.E. Dict. Canting Crew.
[UK]Grose Classical Dict. of the Vulgar Tongue.
[UK]Lex. Balatronicum.
[UK]Egan Grose’s Classical Dict. of the Vulgar Tongue.
[US]Matsell Vocabulum.