When someone has secretiveness, they keep things hidden and don't tell others about them.
Secretiveness can make people feel suspicious or curious about what is being hidden.
Examples:
Her secretiveness made me wonder what she was hiding.
The secretiveness of the situation made me feel uneasy.
I don't like his secretiveness about the plan.
The cat's secretiveness about where it hides is funny.
The secretiveness of the treasure's location made the adventure more exciting.
The secretiveness of the magician's tricks amazed the audience.