on what the Buddha taught
Ariyasāvaka is often found translated as noble disciple.
It is a compound formed with the words ariya and sāvaka. Ariya is said to refer to the generally approved and esteemed customs and ideals of the Aryan clans. It covers the racial, social and ethical aspects, translated as noble. And sāvaka means hearer or disciple.
Noble disciple, though grammatically correct, seems to indicate the disciple as the noble one. But note that for a virtuous one (an arahant, also a disciple) 'just' sāvaka is being used, which makes it a little odd; first be named noble and then not is normally not seen as a good thing. Another rendering is disciple of the noble ones but again, for the virtuous ones 'just' sāvakā is being used. In other words, if for virtuous ones 'noble' falls off it is a bit odd to then use it in 'disciple of the noble one(s)'. Thus both translations leave some oddness by trying to assign noble to a person.
But noble here stood for the social and ethical direction. It is about the hearer, learner of the good, the highest, righteousness, of all of those traits for which Aryan stood example. Ariya is here used as brand generification so to speak. Ariyasāvaka then means something like 'disciple of the good', and how lovely is that? Even when the Buddha's words are gone you can set things as nobler, higher, not to admire but to advance to. Since a virtuous one is done with going, that direction towards the good does not apply.
To stay close to common translations I use disciple of nobleness.
Ariya (adj. --- n.) noble.
---sāvaka disciple of nobleness.