偏正面： 柯林斯：
If you overlook someone’s faults or bad behaviour, you forgive them and take no action. 宽容；宽恕
SYN ignore, excuse, forgive, pardon
…satisfying relationships that enable them to overlook each other’s faults.
能使他们互相包容对方缺点的舒心的关系 朗文：
to forgive someone’s mistake, bad behaviour etc and take no action 不计较﹐宽恕〔某人的过失﹑坏行为等〕
She found him entertaining enough to overlook his faults.
她觉得他很有趣﹐足以让她包容他的缺点。
偏负面： 牛津：
to see sth wrong or bad but decide to ignore it （对不良现象等）不予理会，视而不见
SYN turn a blind eye 佯装不见，睁一只眼闭一只眼
We could not afford to overlook such a serious offence.
对这样严重的违法行为，我们决不能视若无睹。 新牛津：
Ignore or disregard (something, especially a fault or offence) 不理会；宽恕，宽容（某事，尤指过错、冒犯）
she was more than ready to overlook his faults
她很愿意宽恕他的过错。 韦氏：
to pay no attention to (something) 不理会；忽略
She learned to overlook [=ignore] her boyfriend’s minor faults.
她学会了容忍男友的小毛病。
Such a crime should not be overlooked.
对这样的罪行，不应视若无睹。
mid-14c., “to examine, scrutinize, inspect,” from over- + look (v.). Another Middle English sense was “to peer over the top of.” These two literal senses have given rise to the two main modern meanings. Meaning “to look over or beyond and thus not see,” via notion of “to choose to not notice” is first recorded 1520s. Seemingly contradictory sense of “to watch over officially, keep an eye on, superintend” is from 1530s.
两种语言之间本就不存在一一对应的关系。单词的含义要在具体语境中去理解。就overlook而言，看似“对立”的两种释义，都是由其本义引申出来的，只是语境不同罢了。
再遇到类似的情形，就要查词源了，ODE Living 和 蓝登韦氏大学都是值得推荐的，另外 https://www.etymonline.com/ 也很不错。
thanks your post.