Acharya (आचार्य) is not a full form or abbreviation. It is a Sanskrit/Prakrit word.

Word meaning:

• Achar = conduct / right conduct
• Ya = one who

So, Acharya means:

“One who practices and teaches right conduct” or “A spiritual preceptor / teacher who guides monks and followers in Jain Dharma.”

In Jainism:

• follows Jain vows strictly
• teaches the path of Ahimsa, Satya, Asteya, Brahmacharya, Aparigraha
• guides the Sangh and other monks

If you want, I can also give:

• Acharya’s Jain definition
• Acharya Padvi meaning
• difference between Acharya, Upadhyay, and Sadhu