1. A way of speaking, acting, or expressing oneself that is difficult or impossible to understand; incomprehensible method or mode
He spoke in an unintelligible manner that confused everyone in the room.
Ele falava de maneira ininteligível que confundia todos na sala.
2. An unclear or obscure way of doing or presenting something
The professor explained the complex theory in such an unintelligible manner that students left more confused.
O professor explicou a teoria complexa de maneira tão ininteligível que os alunos saíram ainda mais confusos.