形容詞 wayward:

1. resistant to guidance or discipline
   同義詞：contrary, obstinate, perverse

1. That wayward child is very hard to teach.
   那個任性的孩子很難教。

way.ward

adj.（形容詞）
Given to or marked by willful, often perverse deviation from what is desired, expected, or required in order to gratify one`s own impulses or inclinations.See Synonyms at contrary ,unruly
任性的：具有或以任性為特征的，通常與為了滿足某人自己的沖動或癖好所期待、盼望或要求的完全相反參見 contrary,unruly
Swayed or prompted by caprice; unpredictable.
難以捉摸的或反復無常的；無法預言的

來源：
Middle English
中古英語
short for awaiward [turned away, perverse]
awaiward的簡寫 [被擋開的，倔強的]
awai [away] * see away
awai [離開的] *參見 away
-ward [-ward]
-ward [向…的]

【引伸】
way.wardly
adv.（副詞）
way.wardness
n.（名詞）