noun
jack of all trades, master of none
Describes a person who dabbles in many skills but excels at none. A rare, literary term; compare 螻蛄才 (けらざい), which has a similar meaning.
See also: 螻蛄才
彼は螻蛄芸で、何でも少しはできるが、どれも中途半端だ。
He is a jack of all trades and master of none; he can do a little of everything, but nothing thoroughly.
Compound of 螻蛄 (けら, 'mole cricket') and 芸 (げい, 'art, skill'). The mole cricket can dig, swim, and fly but excels at none, giving rise to the metaphorical meaning. The exact historical derivation is uncertain.