1. most secretive, quiet, or careful to avoid being noticed (superlative form of stealthy)

Examples

• The cat was the stealthiest hunter in the neighborhood.
• She made the stealthiest approach to avoid waking the baby.
• The ninja was known as the stealthiest warrior in the clan.
• He used the stealthiest methods to gather information.
• The stealthiest submarines can move undetected underwater.
• Among all the spies, she was considered the stealthiest.