Amos 1, 2
Although there were some outward distinguishing characteristics, essentially a Nazarite was a person whose life was separated unto God, to doing His pleasure rather than their own. Parents could commit their child to God in this manner. Samson and John the Baptist were probably the most well known young men to have taken this oath.
They didn’t cut their hair and they didn’t drink fermented wine … ways they showed the world that they were separated unto God.
The outward appearance really has little import. The true value is in being a person who is dedicated to the Lord’s purposes, pursuing His will for their lives rather than nominally choosing their own career path.
They have the Hand of God all over their demeanor. He ordained their life’s course.