Here are some words that can be considered as full forms of "teacher" in Hindi:
* शिक्षक (shikshak) - This is the most common and widely accepted word for teacher.
* गुरु (guru) - This word means "teacher" or "mentor" and is often used for someone who is respected for their knowledge and wisdom.
* उपाध्याय (upadhyaya) - This word is more formal and is often used for a teacher of Vedic scriptures.
* आचार्य (acharya) - This word is also a formal term for a teacher, especially one who is highly respected for their expertise.
It's important to note that the most appropriate word to use will depend on the context.