(of a punishment) that does not involve a person being sent to prison

As an alternative to prison the judge may choose to give a non-custodial sentence. 法官可能选择无需入狱的判决来代替入狱判决。

not having custody of a child (= the legal right to care for him or her)

A non-custodial parent often has very limited access to his or her children. 无监护权的父母一方通常与孩子接触的机会有限。