adj. 1. Not having or performing a function. [ Narrower terms: cosmetic, decorative, ornamental ] Also See: unserviceable. functional [ WordNet 1.5 ]

2. Not performing or able to perform its regular function; as, the yard was littered with nonfunctional vehicles waiting to be repaired. [ Narrower terms: down(predicate) ]. Antonym: functioning.
Syn. -- malfunctioning, unserviceable, out of order. [ WordNet 1.5 ]