W: (n) conservation [Related to: conserve] ((physics) the maintenance of a certain quantities unchanged during chemical reactions or physical transformations)
S: (v) conserve, preserve, maintain, keep up (keep in safety and protect from harm, decay, loss, or destruction) "We preserve these archeological findings"; "The old lady could not keep up the building"; "children must be taught to conserve our national heritage"; "The museum curator conserved the ancient manuscripts"
S: (v) conserve, husband, economize, economise (use cautiously and frugally) "I try to economize my spare time"; "conserve your energy for the ascent to the summit"
W: (v) waste [Opposed to: conserve] (spend thoughtlessly; throw away) "He wasted his inheritance on his insincere friends"; "You squandered the opportunity to get and advanced degree"