1. lacking knowledge, awareness, or understanding about something; uninformed
I'm completely clueless about how to fix this computer.
Sou completamente sem noção sobre como consertar este computador.
2. unable to understand social situations or behave appropriately
He was so clueless at the party that he kept making awkward comments.
Ele era tão desorientado na festa que continuava fazendo comentários constrangedores.