In some translations, Leviticus 19:27 is interpreted to prohibit haircutting. Other translations, reading similar comments in context elsewhere in Leviticus and in Jeremiah, interpret it to prohibit tattooing or scarring.
Leviticus 19:27 (hair and beard); Numbers 6:5; Judges 13:5; 1 Samuel 1:11 - all of those seem to indicate that not cutting hair is a sign of someone set apart for godly purposes. I Corinthians 11:15 advises that short hair in a woman is a sign of shame. Isaiah and Jeremiah cite hair cutting as a sign of grief.