by Mark Israel
     [This is a fast-access FAQ excerpt.]
Contrary to what you may have read in Xaviera Hollander's book
The Happy Hooker, the "prostitute" sense of "hooker" does NOT
derive from Joseph "Fighting Joe" Hooker (1814-1879), a major
general on the Union side of the U.S. civil war, whose men were
alleged to frequent brothels.  "Hooker" in this sense goes back to
1845 (see AHD3); the U.S. Civil War did not begin until 1861.  It
may come from the earlier sense of "thief" (which goes back to 1567,
"to hook" meaning to steal), or it may refer to prostitutes' linking
arms with their clients.  A geographical Hook (Corlear's Hook in New
York City, or the Hook of Holland) is also possible.