Yagas (vELvi) condemned by kuRaL.
vaLLuvar condemned vedic practices (yaaga):
avichorinthu aayiram vEttalin onRan
uyir sekuththu uNNaamai nanRu.
Quite clearly, ancient tamils called it "avichEgam" Both avi and chegu (sekuththu ) can be found in the kuRaL.
avi + seku + am = avichEgam (tamil ) > abishekam (sanskrit).
As animal sacrifices came to an end or the group practising it gave it up, avichEgam (abishegam) also changed its character and reached its present connotation.
Both the root words are well preserved in kuRaL.
puuvum niirum kondu iRaivanai vazipaduvathu tamizar paNbu.
puu sei > puusai (tamil) > puja (sanskrit).