Jack of all trades, master of none

"Jack of all trades, master of none" is a figure of speech used in reference to a person that is competent with many skills, but spends so much time learning each new skill that they cannot become an expert in any particular one.

The earliest recorded versions of the phrase do not contain the second part. Indeed, they are broadly positive in tone. Such a Jack of all trades may be a master of integration, as such an individual knows enough from many learned trades and skills to be able to bring their disciplines together in a practical manner. This person is a generalist rather than a specialist.