完美 (wán měi) means 'perfect' in the sense of being flawless, without any defects. It is stronger than 理想 (lǐ xiǎng 'ideal'), which describes something that meets one's wishes but may not be flawless, and different from 完备 (wán bèi 'complete'), which emphasizes having all necessary parts. Use 完美 for absolute faultlessness.