Something that is fantastic or excellent

शानदार

English Usage: The party was absolutely spiffing!

Hindi Usage: पार्टी बिल्कुल शानदार थी!

To spruce up or make something look better

सजा-संवारा

English Usage: We need to spiff up the house before the guests arrive.

Hindi Usage: मेहमानों के आने से पहले हमें घर को सजा-संवारा करने की जरूरत है।