asymptomatic

meaning in plain English

A person who has a disease but shows no signs or feels any sickness.

Think a silent thief—someone asymptomatic shows no signs, but the disease is still there, like a hidden burglar.

for example

The health officials found that many of the travelers were asymptomatic, so they seemed fine even though they carried the virus.

Think of someone who catches a bug but never coughs or feels ill. That person is called asymptomatic, because the illness is hidden inside them.