clueless

1. ADJ If you describe someone as clueless, you are showing your disapproval of the fact that they do not know anything about a particular subject or that they are incapable of doing a particular thing properly. 无知的[非正式] [oft ADJ 'about' n]

I came into adult life clueless about a lot of things that most people take for granted. 我成年后，发现自己对大多数人认为是理所当然之事知之甚少。