Black and White

Black is കറുപ്പ്, it is the same in Tamil as well. The root is കറു. It can be seen in other words like കറുക്കുക (to blacken), കറുകറുത്ത (very black) etc.
A related root is കാര്‍്, also meaning black, as in കാര്‍വര്‍ണ്ണന്‍ .

White is വെളുപ്പ്. It comes from വെള്‍്. Other related words are വെള്ള (white, adj.), വെണ്മ (വെള്‍് + മ) brightness.

Interestingly, we can see വെള്‍് in words related to light as well e.g. വെളിച്ചം, വെട്ടം (വെള്‍് + തം).

Another similar-sounding but different root is വെല് (to defeat). One can see it in വെന്നു (വെല് + തു), defeated.