Great. But tyros have nothing to do with the mentoring process, per se, right?
In the three organizations I’ve been in during the last 10 years, mentor has been commonly used as a verb. As in “I’m mentoring John” or “I’m going to mentor Susan.”
And, per the OP, the associated nouns that are used are mentor and mentee.
OK, so we have assignor and assignee, payor and payee, but what about harbor? Why no harbee? Manor–manee? Tractor–tractee? Actor–actee? Rotor–rotee? And if we have goatees, why no goators?
What’s with English, anyway?
no really??? wow! thanks! didn’t think of that!!!
see i can be sarcastic too. 
In seriousness I don’t actually have a decent one at work - and i don’t really trust dictionary.com (for the record it does class Mentor as a verb but only informally).
I wasn’t suggesting that you couldn’t. It was just that my gut feeling that grammatically just because you could say:
employer → employ → employee
didn’t meant that you could therefore say:
mentor → mentor or (“ment” 
) → mentee
that was all.
Does grammar have anything to do with it?
It does if you’re a grammee. 
I’m just going to reiterate my earlier objection to “standee.” At least most other -ee words denote the object of a transitive verb.
For example, an employee is a person who is employed.
An addressee is one who is addressed.
And, if you must, a mentee is one who is mentored.
But standee? One who is standed? I don’t think so. No, in the perverse logic that created this word a standee is one who stands. Surely that should be stander? I refuse ever to use this word, except to denigrate it.
Originally posted by auliya
I’m American and I’ve never heard it used. Even though it’s in my dictionary, I don’t believe it’s a real word and I will never us it. Mentoree sounds better and I think it’s really not that cumbersome.