Describing the profession/occupation of a person who is now retired or doesn’t do that anymore

If someone’s past profession is teaching for example then what do we say for them in a grammatically correct way? The confusion is that if we say “ he was a teacher” it could also mean he is now dead and was a teacher before. So the question is how to best describe a person’s profession who is now retired or doesn’t do that anymore in a grammatically correct way?

As the commenters said, "retired teacher" or "former teacher" are both very clear, and are used commonly in spoken and written text.

In academic contexts, you might also use the term "emeritus", again definition from Dictionary.com:

emeritus, adjective [ ih-mer-i-tuh s ]
(1) retired or honorably discharged from active professional duty, but retaining the title of one's office or position

emeritus, noun, singular [ ih-mer-i-tuh s ]
---> noun, plural e·mer·i·ti [ih-mer-i-tahy, -tee]
(1) an emeritus professor, minister, etc.