Answer

A Tirthankar is an enlightened soul who achieves keval gnan and establishes the Jain fourfold community by showing the path to liberation. A Siddh is a soul that has completely liberated itself from all karma and has attained final emancipation.

Explanation

Tirthankar

• Has a physical body
• Lives in the world and teaches the path of liberation
• Re-establishes the tirtha or spiritual ford for others
• Is an Arihant in the state of omniscience
• After completing the life span, attains moksha and then becomes a Siddh

Siddh

• Has no body
• Is completely free from karma, birth, death, pain, and attachment
• Does not teach or act in the worldly sense
• Resides forever in the Siddhashila
• Is in the final state of liberation

Simple Difference

• Tirthankar = Liberated teacher in the world
• Siddh = Fully liberated soul after leaving the body

Spiritual Understanding

In Jain Dharma, a Tirthankar shows the path, while a Siddh has completed the journey. So, every Tirthankar eventually becomes a Siddh, but not every Siddh was a Tirthankar.

Takeaway

A Tirthankar guides others to liberation, and a Siddh is the soul that has reached complete liberation.