deserter, defector

a person who abandons their duty (as on a military post)

• deviationist — an ideological defector from the party line (especially from orthodox communism)
• draft dodger, draft evader — someone who is drafted and illegally refuses to serve
• renegade, turncoat — someone who rebels and becomes and outlaw

• wrongdoer, offender — a person who transgresses moral or civil law