it's a very famous chinese idiom born in West Han Dynasty. it'a hard to explain it word by word. it's like someone with very limited knowledge and scanty information. but when you use this one to describe yourself, it imples you are a modest guy and you can win respect. cause it shows you are honest. and when you use this one to describe other people . it's a sneer or sacasm to others. e.g: 1. 你今天说的话让我觉得自己太孤陋寡闻了，谢谢你。 what you talked about today really opened my eyes and let me realise i got to do much work to get better, thank you. 2. 那个人非常孤陋寡闻，你不要跟他瞎混。 that guy really sucks, just keep far away from him, ok ?

出處:《禮記‧學記》：「獨學而無友，則孤陋而寡聞。」 單字釋義: 孤：單獨，獨自學習；陋：淺陋；學識淺薄；寡：少；聞：知識。 釋義: 形容學識淺陋，見聞不廣。

来源于《礼记·学记》中的“独学而无友，则孤陋而寡闻。指“学识浅薄，见闻狭窄”。其实大多数中国人日常用的成语也不多。