Special move

A Special Move is any move that is activated by pressing the special move button (usually O). They were first introduced in the Super Smash Flash series in Super Smash Flash 2. Special moves include the standard special move, side special move, up special move, down special move, and Final Smash. All neutral special moves can be used by Kirby because of his neutral special; Inhale.

Uses
Special moves are usually (but not always) attacks that deal more damage than normal attacks, but cause less knockback. Most special moves are often a character's signature move(s), such as Captain Falcon's Falcon Punch and Goku's Kamehameha. Special moves have many different uses, and may differ from each other in effect. Most projectiles can only be launched through special moves, such as Mario's Fireball, and most up special moves are used as a third jump to recover. However, most moves that aid in recovery render the user helpless when used in the air.

Final Smash
A Final Smash is a special type of special move that can be activated by obtaining a Smash Ball through breaking it using attacks. It is activated by pressing the special move button, like you would when doing a Standard Special. A Final Smash often does a attack which deals high amounts of damage and knockback. However, some Final Smashes involve the player transforming into an advanced form, where their attack's power are often increased. This is called a Final Form. A Final Form that does not have a complete moveset, or has about 1-3 attacks is called a Semi-Final Form.