E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
Wool.
Dyed in the wool. A hearty good fellow. Cloth which is wool-dyed (not piece-dyed), is true throughout “and will wash.”
1
No wool is so white that a dyer cannot blacken it. No one is so free from faults that slander can find nothing to say against him; no book is so perfect as to be free from adverse criticism.
