1.Definition: kept in reserve especially for emergency use
"A spare tire", "Spare parts"
2.Definition: lacking embellishment or ornamentation
Related Adjective(s):bare, plain, unembellished, unornamented
4.Definition: more than is needed, desired, or required
"Sleeping in the spare room"
Related Adjective(s):excess, extra, redundant, supererogatory, superfluous, supernumerary, surplus
5.Definition: not taken up by scheduled activities
"Spare time on my hands"
6.Definition: thin and fit
"The spare figure of a marathon runner"