Imu has the hikimayu eye brow which means she is a woman
The hikimayu eye brow is a practice only for woman. You won't see it in any other male character in manga/anime.
The original hikimayu eyebrow should be a small patch of smudged paint like this.
Otoko is a girl and she has hikimayu eyebrow.
But you know Oda's style of eyebrow is just a normal eyebrow. Or rather no eyebrow at all.
Yeah Imu eyebrow isn't exactly hikimayu style at all, but Oda might change it up creatively in a different way. The eyebrow is very short and closer to the center which is rare in One Piece. Male character doesn't has this kind of eyebrow because it contradict to the masculine look. This is one of the evidence that could make Imu closer of being a woman.
The hikimayu eye brow is a practice only for woman. You won't see it in any other male character in manga/anime.

The original hikimayu eyebrow should be a small patch of smudged paint like this.

Otoko is a girl and she has hikimayu eyebrow.

But you know Oda's style of eyebrow is just a normal eyebrow. Or rather no eyebrow at all.

Yeah Imu eyebrow isn't exactly hikimayu style at all, but Oda might change it up creatively in a different way. The eyebrow is very short and closer to the center which is rare in One Piece. Male character doesn't has this kind of eyebrow because it contradict to the masculine look. This is one of the evidence that could make Imu closer of being a woman.