Sometimes, not knowing the things and admitting to the same, may be the best way to learn quickly and teach others at the same time.
It saves you from knowing yourself clearly what you know and what you don’t know.
At the same time, it shifts the onus to other person on helping you know that thing (mostly).
Being an imposter would not take you anywhere in the long run but learning the things along the journey will.
In an interview, for example, if you say ‘I don’t know’ to a question, it simply lends credibility to everything else that you have said.