unknowledgeable

US /ˌʌnˈnɑː.lɪ.dʒə.bəl/
UK /ˌʌnˈnɑː.lɪ.dʒə.bəl/
1.

ไม่รู้

not knowing a lot:

:
The sales clerk was frustratingly unknowledgeable about the product range.