頑是無い (がんぜない) Japanese meaning | KotomoraMeanings
1
i-adjective
innocent; helpless
Describes a child or young person who is naive, unaware of the world, and unable to fend for themselves. Often carries a gentle or pitying tone.
彼女の頑是無い笑顔を見ると、守ってあげたくなる。
Seeing her innocent smile makes me want to protect her.