One letter makes all the difference:

The adjective tortuous means winding, crooked, marked by repeated twists and turns. In an abstract sense, it can also mean complex, devious, complicated, tricky to handle:

• They had to take a tortuous route over the mountains to escape.
• The path to peace in the Middle East is still as tortuous as it has ever been.
• The plots of soap operas become increasingly tortuous as they compete to attract viewers.

The adjective torturous means painful in a cruel way, causing torture, or extremely slow and difficult:

• Training for a marathon can be a tedious and torturous business.
• He survived six torturous years in the jungle after being kidnapped by guerrilla fighters.
• The audience sat for three torturous hours through the out-of-tune school production.

Extra Similar Words

 The adjective tortured means receiving torture or pained:

• The beggar put on a tortured look in order to attract the sympathy of passers-by.

The adjective tortious is a legal term meaning of or relating to tort i.e. damage, injury, or a wrongful act done wilfully, negligently, or in circumstances involving liability:

• The county court judge had to decide whether the man’s severe pruning of his neighbour’s hedge amounted to a tortious act.