Here are Jain-friendly boys’ names starting with S, with simple meanings. I’ve kept the meanings close to Jain usage where possible:

• Siddharth — one who is accomplished; in Jainism often used for a perfected soul or a liberated being.
• Suryakant — beloved of the sun; symbolic of brilliance and clarity.
• Samar — companion in virtue; balance of strength and serenity.
• Sanjit — victory; bringing success with calmness.
• Satyendra — lord of truth; someone who embodies truth.
• Saket — a name of a pure, peaceful realm; often used to denote purity.
• Saanvi — (more commonly a girl name, but sometimes used for boys in some communities) meaning someone who is celebrated; light.
• Shantanu — calm, peaceful; tranquil by nature.
• Shreyansh — best portion; excellent, auspicious.
• Sidharth — achiever of spiritual goals (often linked to Jain/Spiritual context as a liberated being).
• Sujal — pure and dignified; sincere.
• Suvrat — one who keeps good vows; virtuous.

If you’d like, tell me a bit about the feel you want (traditional, modern, unique, religious emphasis), and I can tailor a shorter, more focused list.