JK> Does anyone know the difference in meanings between
JK> kilesa and uppakkilesa? The dictionary definitions
JK> suggest defilement or impurity for both. What
JK> subtlety of difference does the upa- prefix bring, if
JK> any?
On the second glance, I think that besides the tinge of 'on, upon',
there's also a shade of 'coming close from down under'. That is,
'upakkilesaa' are considered to be somewhat lower, or secondary,
adjoining, to those things on which they appear.