double down

/D AH1 B AH0 L D AW0 N/
verb
  1. 1

    To double one's wager. In particular, it is the name of a specific doubling bet allowed in blackjack.

  2. 2

    (by extension, often followed by the preposition on) To double or significantly increase a risk, investment, or other commitment.

Source: https://en.wiktionary.org/wiki/double%20down