Arihant cheiyanam is not a standard, widely used phrase in core Jain texts, so its exact meaning depends on context. Breaking down the words in Jain usage:

• Arihant: a perfected soul who has conquered inner passions (kama, krodha, lobha, moha, mada, matsarya) and has attained omniscience (kevala jnana). An Arihant is a liberated, enlightened being who teaches righteous conduct, but still bears a body until final liberation.

• Cheiyanam (cheiyana/cheiyyanam in some languages): deeds, actions, or conduct; virtuous activities and the code of conduct associated with a spiritual goal.

Putting them together, arihant cheiyanam can be understood as:

• the deeds, conduct, or virtuous activities associated with an Arihant, i.e., the exemplary conduct and teachings of an enlightened being; or
• the merit/means by which an Arihant upholds and propagates dharma for the guidance of others.

If you have a specific text, stanza, or regional usage (for example Tamil or a particular Jain tradition), please share that exact form or context and I can give a precise, tradition-specific interpretation.