economise in WordNet English dictionary

1. use cautiously and frugally
   "I try to economize my spare time"; "conserve your energy for the ascent to the summit"
   conserve  husband  economize  economise 
   
2. spend sparingly, avoid the waste of
   "This move will save money"; "The less fortunate will have to economize now"
   save  economize  economise 
   

economise in English Wiktionary