functional in WordNet English dictionary

1. designed for or capable of a particular function or use
   "a style of writing in which every word is functional"; "functional architecture"
   functional 
   
2. involving or affecting function rather than physiology
   "functional deafness"
   functional 
   
3. relating to or based on function especially as opposed to structure
   "the problem now is not a constitutional one; it is a functional one"; "delegates elected on a functional rather than a geographical basis"
   functional 
   
4. (of e.g. a machine) performing or capable of performing
   "in running (or working) order"; "a functional set of brakes"
   running  operative  functional  working 
   
5. designed for or adapted to a function or use
   "functional education selects knowledge that is concrete and usable rather than abstract and theoretical"; "functional architecture"
   functional 
   
6. fit or ready for use or service
   "the toaster was still functional even after being dropped"; "the lawnmower is a bit rusty but still usable"; "an operational aircraft"; "the dishwasher is now in working order"
   functional  usable  useable  operable  operational