"Cheveux" if it's on the head.
"Poil" if it's anywhere else on the body :D.
His hair is "ses cheveux" (masc.) in French.
a hair bun is 'un chignon' in French.
Long hair is: les cheveux longs in French.
Blue hair is 'les cheveux bleus' in French.
French people in the west and east have brown hair. French people in the south and north have dirty blonde hair, orange hair, or something like that.
ginger hair is 'les cheveux roux' in French.
Long hair is "les cheveux longs" in French.
'messy hair' in french is 'cheveux en désordre'
far hair
hair = cheveux
An hair tie is "un élastique à cheveux" in French.
To have long black hair is "avoir de longs cheveux noirs" in French.