Usually implies strong self-confidence. You defend your opinion without being aggressive. The manager tried to intimidate him, but he held his ground.
Pro Tip 2/3
Social Pressure
Often used when someone resists changing their stance despite group pressure. Even though everyone else agreed, she stood her ground and didn't concede.
Pro Tip 3/3
Moral Conviction
Can suggest holding onto beliefs that are ethical or have personal significance. He held his ground on his vegan beliefs despite ridicule.