noun

• (poker) A form of poker in which the lowest-ranking poker hand wins the pot. Usually the ace is the lowest-ranking card, straights and flushes do not count making the best possible hand being A, 2, 3, 4, 5 regardless of suits (in contrast to deuce-to-seven lowball.)

verb

• (transitive) To give an intentionally low estimate of anything, not necessarily with deceptive intent.
  "It may be, but it is worth noting that if the mortality rate is as low as 0.7% as some experts now hope rather than between 3 and 5% as the data suggests so far, that is still a lot of dead Americans. Californian health officials are bracing for a 56% infection rate. In New York, they are talking about a range of between 30% and 80%, so if we just lowball that, that is close to seven hundred thousand dead Americans as a result of COVID-19. Modeling based on current social and economic disruption actually puts the number at 1.2 million people dying, all the way up to 2.2 million if no measures are taken to reduce contagion and the virus is allowed to run its course."
• (transitive) To give (a customer) a deceptively low price or cost estimate that one has no intention of honoring or to prepare a cost estimate deliberately and misleadingly low.
  "A few other news flashes from the interview: The president of the United States thinks that the government should not pay its bills in full. It should lowball its contractors and force them to accept half payment, he said."
• (transitive) To make an offer well below an item's true value, often to take advantage of the seller's desperation or desire to sell the item quickly.