An unexpected gain or advantage.

A financial gain that is unexpectedly received.

अप्रत्याशित आर्थिक लाभ

English Usage: The sale of the old car turned out to be a nice windfall.

Hindi Usage: पुरानी कार की बिक्री एक अच्छा अप्रत्याशित आर्थिक लाभ साबित हुआ।