His hair is "ses cheveux" (masc.) in French.
a hair bun is 'un chignon' in French.
You can say "Il a des cheveux gris" in French to mean "He has gray hair."
Long hair is "les cheveux longs" in French.
'messy hair' in french is 'cheveux en désordre'
ginger hair is 'les cheveux roux' in French.
les cheveux
Coiffeur
mes cheveux
An hair tie is "un élastique à cheveux" in French.
You would say "cheveux lisses" in French.
"J'aime tes cheveux." = "I like your hair."