saMskR^ita terms for enemies have some interesting social connotations. Below we discuss some of these angles
sapatna- a rival or an enemy. In a strict usage related to rivals for the same woman or competing for lordship over the same object. The adjectival derivative sApatna could also mean children sharing only one common parent and thereby potential rivals due to lower gene-sharing that real sibs.
bhrAtR^ivya- a rival. Bears a connection with the word bhrAta, meaning brother. Members of the same brotherhood may have intense competition for lebensraum. Eg. duryodhana and yuddhiShThira
ari- a rival. Could also mean, in-laws or the exogamous community with which one maintains marital ties. They are the “in-group” rivals. Thus the collection of ari-s into which one marries are the Arya (the ethnonym Arya).
pR^itanA- a hostile agent or army. It could also mean a body of men. Such a body of men could be potential threat to others.
amitra- Not a friend.
shatru- enemy, plain and simple.
dviSha- a hater.