Roleplaying means a lot of different things to a lot of different people, and I think that's good.
To many people, "roleplaying" is battlematting around - "I'm playing what's labeled as a roleplaying game, and it's about minis combat, therefore minis combat is roleplaying." Or creating a compelling story (where that can mean interesting, or realistic, or...).
Often by "roleplaying," when people try to stress it as a distinct activity within a RPG, it often means more "character-focused" roleplaying, though that also has sub-variations people don't agree on - "character simulation" vs "actor stance" vs "immersion" for example. We need a better, more specific name for this activity, which may be a mix of the following.
"Character simulation" encompasses
games where there are personality
mechanics that affect your behavior.
(Pendragon's a good example.)
"Acting" is, well, acting out your
character. When people say "funny
voices!" this is what they mean.
"Immersion" is being able to actually
put yourself inside your character.
It's different from acting in that
it's more "method acting" as opposed
to "just acting."
Anyway, history shows that trying to use the term "roleplaying" for "character portrayal" will inevitably end in this kind of flame war from those who think saying that their activities they prefer in an RPG are being looked down upon because they're not in that definition. Therefore we should avoid that. And besides, even "roleplaying" isn't precise, as seen above.
I propose that questions etc. about "roleplaying" say what they actually mean. "What games mechanically reward portraying your character's personality quirks" is a both less hassle-magnetic title and is also really precise. And it is distinct from "What games encourage character immersion" or "What games contain prescriptive personality mechanics,
all good questions that do not benefit from conflation.