In Terapanth (Śvetāmbara Terāpanth sampradāy), this question is mainly about community custom, not about a specific Jain scriptural rule.

1. From Jain dharma side (general principle)

- Jain scriptures do not go into detailed blood‑relation degrees (like 1st cousin, 2nd cousin etc.) for marriage rules. - The main stress is on: non‑violence, good character, and a pure grihastha life. - So, there is no direct Jain‑dharma sutra that says “second cousin marriage is allowed/not allowed”.

1. From Terapanth / Jain samaj side (practical custom)

- Most Jain communities, including Terapanth, strongly avoid close‑blood marriages. - Generally, they avoid marriage: - within the same close family line, - within restricted gotra / kul according to their local rules, - and anything that socially feels like “near cousin” marriage. - Whether your community counts second cousin as “too close” can vary by: - local Terapanth samaj rules, - family tradition, - and sometimes medical/ethical advice.

1. What you should do in practice

- Do not rely only on a generic yes/no from anyone online. - Speak to: - your local Terapanth samaj leaders or marriage committee, - and an elder (pañch / nyat / kul‑purohit type guide) who knows your exact family tree (khandān, gotra, kul). - They will tell you clearly whether your specific match is: - religiously acceptable, - medically sensible, and - socially approved in your Terapanth circle.

In summary: Jain dharma itself does not explicitly forbid or permit “second cousin marriage” by name, but Terapanth community practice usually discourages marriages in very close relations. For your exact case, final guidance must come from your local Terapanth authorities and family elders who know both lineages clearly.