Hakama are unisex pleated "pants" which can either be in a skirt style (gyoto hakama) or divided into two like baggy trousers (umanori horse-riding hakama) - traditionally worn over a full kimono.
The waist is generally a free size since the front and back panels are joined by long ties that can be doubled around the waist on smaller frames.
Men traditionally wear the hakama low on the hips; Japanese women wear theirs high at the waist. Hakama are good for martial arts or make a unique skirt for women.