On the left side — a euphemism, as the literal meaning is 'well-named' or 'of good name' (eu + onoma). The Greeks considered the left side unlucky and used this positive-sounding word to avoid saying 'left' directly. In the New Testament, it appears in contexts of judgment (sheep on the right, goats on the left) and the request of James and John.
Euonymos carries the weight of eschatological separation. In Matthew 25:33, the goats are placed on the euonymos — the left. Despite the word's euphemistic 'good name,' the position is one of judgment. When James and John asked to sit at Jesus's right and left (Mark 10:37), they didn't understand that the 'left' of Jesus at His glorification was a cross — the two thieves occupied those positions. The word teaches us to be careful what we request from God.