To get in and stay in, or to approach safely and punish (usually with range)? First would generally be rushdown, second would generally be a mid-range zoner.
Rushdown is generally defined by fast and usually safe normals, coupled with good mixups.
A zoner's main goal is of course to keep the opponent out, but those that operate best at mid-range (most incarnations of Chun-Li[?]) I guess are, at least in SF, referred to as footsie characters, built to punish mistakes made by the opponent by throwing out unsafe or whiffed normals that are usually hard to punish, while fishing for failed punish attempts.
Basic descriptions that don't go into too much detail and will likely incite annoyance among nitpickers, but that's all I have the energy for right now.
I think it has more or less to do with the speed of a character and the speed of their attacks. Like example Raiden and Drake are characters who can approach well. Big Daddy and Sir Dan are characters that cannot and require much more care to not get killed.
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