IE words for spleen

I´ve been looking for an etymological explanation for the french word
for spleen, rate, but haven´t been able to find it. To me, rate,
seems celtic but since I´ve found out that the celtic words correspond
to the latin lien and greek splen I don´t know what to think. Also,
the spanish word boza and the german Zorn seems to be unexplainable by
looking them up on the internet.
Can anyone here help me with all this?

Carl