WordWeb Online

1. Not causing disapproval
   "unobjectionable behaviour";
   - innocuous
    
2. Not objectionable
   "the ends are unobjectionable; it's the means that one can't accept"
    
3. (of behaviour or especially language) free from objectionable elements; fit for all observers
   "good unobjectionable fun";
   - clean

See also: acceptable, antiseptic, decent, inoffensive

Antonym: dirty