You want to have a sword and shield, and get up in everyone's face...you're a Fighter.
You want to have a spear and short bow to strike from reach/range...you're a Fighter.
You want to be a dual-wielding hand-axe dude...ok, fine, once upon a time you needed to be a Ranger for 2-weapon fighting, but in this day and age...you're a Fighter. And even then, a ranger is/was just a sub-class of Fighter.
You want to be a grizzled veteran with a heavy crossbow who is past putting himself in harm's way...you're a Fighter.
You want to wear a fur bikini and carry a battle axe....you're a Fighter. You can be a Barbarian...but you don't have to be.
You want to wear plate and carry a shield with a broad sword, acting as "defense" more than "offense"....yes, you are a Fighter. Unless you want to include the "religious" element to your character in which case, we'll call you "Paladin"...or not if you don't want (a character can have a religious bent without all out "devotion" and "godly intervention").
A soldier, a knight, a lightly-armored heavily-armed mercenary, an archer, a swordsman/axeman/spearman, a monster-hunter, a treasure-hunter...you're a Fighter.