v.1. To delete or erase something: I went back to the list and canceled out my name. Realizing the total was incorrect, I canceled it out and recalculated the price.
2. To equalize or make up for something; offset something: Today's decline in the stock's price canceled out yesterday's gain. We made record progress last month, but the delays this month have canceled it out. I never go to the beach because the fun of swimming in the ocean and the difficulty of getting to the beach cancel out.
3. To remove a common factor from both sides of a mathematical equation: After I canceled out the common factors, I could easily solve for the variable. When two factors are equal, you can cancel them out.
4. To withdraw from something, as an activity or obligation: They had dinner reservations with us, but they had to cancel out when they couldn't find a babysitter.
5. Slang To murder someone: The loan shark threatened to cancel me out if I didn't pay him the money. The gangsters vowed to cancel out any rivals.