"My mom is a pensioner."

Translation: Моя мама - пенсіонерка.

[flootzavut]

I thought it said in the notes that you didn't have to use the feminine forms? is this only with certain nouns?

[TobyBartels]

I just wrote пенсіонер, and it was accepted without complaint.

[TobyBartels]

Does this mean literally someone who receives a pension, to be said in the context of some job, contrasting with those who are not yet retired, as in the U.S.; or does it simply mean any older person, who is eligible perhaps for some government old-age programme, as in (as I understand it) the UK?

[max.goncharuk]

Yes, usually this means "literally someone who receives a pension, to be said in the context of some job". Here in Ukraine more or less all the people can have some pension after retire despite that is could very small funds.

[ChristinaSuko]

"Моя мама на пенсії" should also be accepted.