I was wondering how could I remove one (wrongly inserted) entry/word from the ispell private-dictionary.
EDIT
after more digging i am still unab
On my cygwin install ispell is just a wrapper around aspell:
cygwin
ispell
aspell
$ ispell Ispell compatibility script for Aspell. Usage: /usr/bin/ispell [options] -a|-l|-v[v]|-c|-e[1-4]|
If that is true of your installation, then you need to look at aspell files. Try aspell dump config.
aspell dump config