splurge

Short definition from Wiktionary

Verb

1. 1
   To (cause to) gush; to flow or move in a rush.
2. 2
   To spend lavishly or extravagantly, especially money.
3. 3
   To produce an extravagant or ostentatious display.

Noun

1. 1
   An extravagant or ostentatious display.
2. 2
   An extravagant indulgence; a spending spree.