spare

Concise Oxford English Dictionary © 2008 Oxford University Press:
spare/speə(r)/

▶adjective

• 1 additional to what is required for ordinary use.

  ■ not currently in use or occupied.

  ■ (of time) available for leisure.

• 2 with no excess fat; thin.

• 3 elegantly simple.

▶noun

• 1 an item kept in case another item of the same type is lost, broken, or worn out.

• 2 (in tenpin bowling) an act of knocking down all the pins with two balls.

▶verb

• 1 give (something of which one has enough) to (someone).

  ■ make free or available.

• 2 refrain from killing or harming.

  ■ refrain from inflicting (harm) on (someone): they have been spared the violence.

• 3 archaic be frugal.

– phrases
go spare Brit. informal become extremely angry or distraught.
spare no expense (or no expense spared) be prepared to pay any amount.
to spare left over.

– derivatives
sparely adverb,
spareness noun.

– origin OE spær ‘not plentiful, meagre’, sparian ‘refrain from injuring or using’, of Gmc origin.