1. With the utmost strength or loudness.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• forttissimo,
• dortissimo,
• cortissimo,
• vortissimo,
• gortissimo,
• tortissimo,
• rortissimo,
• firtissimo,
• fkrtissimo,
• flrtissimo,
• fprtissimo,
• f0rtissimo,
• f9rtissimo,
• foetissimo,
• fodtissimo,
• foftissimo,
• fottissimo,
• fotissimo,
• fortissimoo,
• fourtissimo

• forties,
• fort smith,
• forty-six,
• fortson.

The adjective form of "fortissimo" is "fortissimo". This word is used to describe a very loud or powerful musical passage or performance.

The plural of the "fortissimo" can be the "fortissimos".

The singular of the "fortissimo" can be the "fortissimo".