In the following set of words, which is different than the others?

Question

Quizplus · Accepted Answer

To be chastened is to be restrained or "reeled in" after being punished. It is similar to the word 'chastised'. Chasten is not similar to the rest of the words in this set because it does not pertain to impetuous and rash ways of life.
Reckless is defined as 'heedless of danger or the consequences of one's actions'. 
Wild is defined as "lacking restraint; uninhabited and not domesticated'. 
Venturesome is defined as 'willing to take risks or embark on unusual, dangerous courses of action'. 
Unbridled is defined as 'uncontrolled and unconstrained'.

In the Following Set of Words, Which Is Different Than