'Enemy' in the Bible

Then Saul was even more afraid of David, and Saul was David's enemy from that time on.

Then Saul told Michal, "Why did you deceive me like this and let my enemy go so he could escape?" Michal told Saul, "He told me, "Let me go or I'll kill you!'"

David's men told him, "Look, today is the day about which the LORD spoke to you when he said, "I'll give your enemy into your hand.' Do to him whatever you want!"

For who would find his enemy and then send him away safely? May the LORD repay you for what you have done for me today.

Abishai told David, "Today God has delivered your enemy into your hand. Let me run the spear through him into the ground with a single blow. I won't need to strike him twice!"

Samuel said, "Why do you ask me, since the LORD has departed from you and become your enemy?