I couldn't miss the chance to practice my drawing!
Silence Blade (サイレス剣, Sairesu Ken?), also known as Silence Sword, Muted Slash, or simply Silence or Mute, is a recurring ability in the series. It is generally a mid-powered Spellblade ability, either giving the user the ability to inflict the Silence status with physical attacks as long as they don't use another Spellblade ability or outright dealing damage. It generally requires the Silence spell in order to use it.
Silence is a level 2 Spellblade ability that costs 1 MP to cast. It makes the user's physical attacks non-elemental in addition to giving the chance to inflict Silence on each physical attack.
Silence Blade is a rank 2 Command Materia that costs 6 AP to use. It can be stolen from Scissor Claw and Iron Claw, found during Mission 8-6-2, or acquired by delivering a HP Mako Stone to the Materia Room in the Shinra Headquarters. Silence Blade is a physical attack that inflicts Silence to the target.
Silence is a level 2 Sword Magic. It imbues a weapon with the status ailment silence for ten turns and has a 75% chance to cause silence in one target when attacking. It costs 5 MP to use. It can be bought Ancheim for 400 pg.
Muted Slash is an ability of the Magic Blade skillset, usable by the Red Mage. It costs 8 MP to use and inflicts physical damage as well as Silence.