He is acting in a way that is like 'hide the head but forget the tail'.

He lied to conceal the truth.

It was revealed that he had a hidden weapon.

He installed a hidden camera in the room.

He stuck to his first thought or decision.

He was troubled by various thoughts.

He recites a Buddhist invocation every day.

His thoughts were so deep that we couldn't understand them.

His new idea brought a new perspective to our project.

He had no choice but to resign to the situation.