na-adjective, noun
perfection; completeness; thoroughness
Describes a state of being perfect, complete, or thoroughly done, often used in formal or literary contexts. As a な-adjective, it modifies nouns to mean 'perfect' or 'complete'.
彼の計画は十全とは言えない。
His plan cannot be called perfect.
十全な準備が必要だ。
Thorough preparation is necessary.
The word is composed of 十 (ten, complete) and 全 (whole, all), suggesting the idea of 'ten out of ten' or total completeness. The exact historical derivation is uncertain.