spare

refrain from harming

save or relieve from an experience or action

• “I”

give up what is not strictly needed

• “he asked if they could spare one of their horses to speed his journey”

use frugally or carefully

thin and fit

• “the spare figure of a marathon runner”
• “a body kept trim by exercise”

more than is needed, desired, or required

• “trying to lose excess weight”
• “found some extra change lying on the dresser”
• “yet another book on heraldry might be thought redundant”
• “skills made redundant by technological advance”
• “sleeping in the spare room”
• “supernumerary ornamentation”
• “it was supererogatory of her to gloat”
• “delete superfluous (or unnecessary) words”
• “extra ribs as well as other supernumerary internal parts”
• “surplus cheese distributed to the needy”

just sufficient

• “the library had a spare but efficient look”

not taken up by scheduled activities

• “a free hour between classes”
• “spare time on my hands”

kept in reserve especially for emergency use

• “a reserve supply of food”
• “a spare tire”
• “spare parts”

lacking in amplitude or quantity

• “a bare livelihood”
• “a scanty harvest”
• “a spare diet”

an extra component of a machine or other apparatus

an extra car wheel and tire for a four-wheel vehicle

a score in tenpins; knocking down all ten after rolling two balls