He was young but his hair had already turned white.
Tips
culture
白头 evokes growing old in Chinese poetry. The classic phrase 白头偕老 ("together until our hair turns white") is the standard wedding blessing, the Chinese equivalent of "till death do us part".
memory
Literally "white head" = white-haired = old. Same logic as 白发 ("white hair"). The bird 白头翁 ("Chinese bulbul") gets its name from its white crown.
