also: ぴんさつ
crisp new banknote
Colloquial term for a brand-new, unwrinkled bill, often used when giving money as a gift or for special occasions.
I prepared the New Year's gift money in crisp new bills.
I had the money exchanged for crisp new bills at the bank.
The ピン part likely comes from the onomatopoeic or mimetic word ピン, suggesting something taut or crisp, combined with 札 (bill). The exact derivation is uncertain.