Select the most appropriate synonym of the given word.

ARDUOUS

Difficult 

The most appropriate synonym of the word "arduous" is difficult.

• Arduous means requiring great physical or mental effort.
• Difficult means requiring much effort or skill to do.
• Constricted means made narrow or smaller.
• Draught means a current of air moving through a confined space.
• Enormity means something that is extremely large or great.