noun

• (Islam) A holy war undertaken by Muslims.
  "Young Iraqis of both sects obeyed the imams' ruling last week by rushing to conscription offices in hot, dirty, dusty Bagdad to offer themselves or their money for the jihad."
• (Islam, theology) A personal spiritual struggle for self-improvement and/or against evil.
  "As a result, Amirull has renounced his radical beliefs in armed jihad and the use of violence. He now sees jihad as caring for his parents, improving himself, and contributing to society."
• (by extension) An aggressive campaign for an idea.
  "And now, the prophecy. One will come, the voice from the outer world, bringing the holy war, the jihad, which will cleanse the universe and bring us out of darkness."