Pound-foolish

Origin

From penny-wise and pound-foolish ("thrifty in the small and wasteful in the large")

Full definition of pound-foolish

Adjective

1. Being unwise in dealing with large amounts of money.
• 1976, MI Roemer, Response to MK Chen, Accordingly, by Dr. Chen's method of calculation, the copayment experience would have to be deemed even more pound-foolish than we found it to be.