After being scolded by the teacher, the proud student was clearly chastened and became much more humble.

chastened 是动词 chasten 的过去分词形式。chasten 的意思是"惩戒、责罚"，通常指通过批评或惩罚使人改正错误行为或态度。在这里表示"受到惩戒后变得谦逊"的状态。