Is it safe to use "old" to mean "previous" for a person?

Is it safe to use "old" to mean "previous" or "former" for something like "my old teacher"? Or is it a bit risky, because "old" also has a meaning with respect to age (i.e., chronologically gifted)?

Wiktionary doesn't give any warnings about "old" potentially causing offense. But should it be avoided in this context anyway?

Solution 1:

It's perfectly acceptable. While I suppose that old could be misconstrued to mean aged, it's unlikely to be misinterpreted as such in context.

Here's a dictionary confirmation:

7: former
his old students

A real-world example using variants of old and former to describe students and teachers can be seen here.

Solution 2:

If they are your enemies and you must talk delicately, then say former. Otherwise, you are a-ok.