adj

• (UK, informal) Very angry; frustrated or distraught.
  "When he found out that someone had broken the window, he went spare."

noun

• (bowling) The right of bowling again at a full set of pins, after having knocked all the pins down in less than three bowls. If all the pins are knocked down in one bowl it is a double spare; in two bowls, a single spare.
• (bowling) The act of knocking down all remaining pins in second ball of a frame; this entitles the pins knocked down on the next ball to be added to the score for that frame.
• (Canada) A free period; a block of school during which one does not have a class.
  "I also remember watching David Letterman's short-lived morning show on TV when I had a spare during my school schedule."
• (Myanmar) assistant or extra hand (typically on buses and lorries)

verb

• To show mercy, to have mercy on.
• To show mercy, to have mercy on.
• To show mercy, to have mercy on.
  "For jealousy is the rage of a man: therefore he will not spare in the day of vengeance."
• To show mercy, to have mercy on.
  "Kill me, if you please, or spare me."