lights are on but nobody is home

the lights are on but nobody is home

Meaning:

• used to describe a stupid person
• something that you say when you think someone is stupid
• when someone does not react because they are thinking about something else
• have a brain, but not using it
• used to tell that someone lacks cleverness or alertness

Examples:

1. I tried all to understand him, but the lights are on but nobody is home.
2. John has no idea about this – the lights are on but nobody's home.
3. Lilly studied about interior designing but the lights are on nobody is home.