gratuitous in WordNet English dictionary

1. costing nothing
   "complimentary tickets"; "free admission"
   complimentary  costless  free  gratis  gratuitous 
   
2. without cause
   "a gratuitous insult"
   gratuitous 
   
3. unnecessary and unwarranted
   "a strikers' tent camp...was burned with needless loss of life"
   gratuitous  needless  uncalled-for