n someone who refrains from injuring or destroying
s thin and fit
s more than is needed, desired, or required
s not taken up by scheduled activities
s kept in reserve especially for emergency use
s lacking in amplitude or quantity
s lacking embellishment or ornamentation
[医] 节省物质(一种由于自己在代谢中破坏而能减少其他物质破坏的物质)