Perfect means finished and complete. A perfected Christian is one who has the fruit of the Spirit, is complete in all understanding.
2Chronicles 8:16 Now all the work of Solomon was prepared unto the day of the foundation of the house of the LORD, and until it was finished. So the house of the LORD was perfected.
Colossians 4:12 Epaphras, who is one of you, a servant of Christ, saluteth you, always labouring fervently for you in prayers, that ye may stand perfect and complete in all the will of God.