A jack of all trades is a master of none.

What it means

Someone who does a little of everything reaches real depth in nothing. Used of people, and increasingly of teams and products that try to serve every case at once.

Where it comes from

“Jack of all trades” was originally plain praise for a capable all-rounder; the dismissive tail “master of none” was added in the late eighteenth century and turned the compliment into a warning. The longer version now widely quoted — “but oftentimes better than a master of one” — is a modern revival rather than the historical original, so it is best not presented as the “real” full saying.

Example sentences

• “The tool does email, chat and invoicing badly — a jack of all trades is a master of none.”
• “Pick one instrument and stay with it, or you’ll be a jack of all trades and a master of none.”
• “She resisted the label, pointing out that breadth was exactly what the role needed.”

When it fits — and when it does not

Mildly insulting about a person, so it is safer about a product than a colleague. If you use the flattering longer version, present it as a modern rejoinder, not as the original.

Similar phrases

• Do not spread yourself too thin.
• Fall between two stools.