adios vs farewell

adios

• goodbye 

• A goodbye. 

• To get rid of. 

• To leave; to literally or figuratively say “adios” to. 

farewell

• Goodbye. 

• A departure; the act of leaving 

• A wish of happiness or safety at parting, especially a permanent departure 

• Parting, valedictory, final. 

• To bid farewell or say goodbye.