This is the 4490th most frequent Japanese word.
完璧
Perfect; flawless.
In this case, 完璧 (kanpeki) refers to the concept of perfection as a goal or standard to achieve.
私は試験で完璧を目指しました。
I aimed for perfection in the exam.
In this sentence, 完璧 (kanpeki) describes the state of the painting being without flaws or being ideal.
この絵は完璧です。
This painting is perfect.
Here, 完璧 (kanpeki) is used as an adjective (when combined with the particle な) to describe the person as embodying ideal qualities.