Answer: functional

AnswerCrossword Clue
functionalserving a function / something that serves a function
functionalOf or relating to a variable quantity whose value depends on one or more other variables
functionalDesigned to be practical and useful, rather than attractive
functionalOf or having a special activity, purpose, or task; relating to the way in which something works or operates
functional(of a disease) Affecting the operation, rather than the structure, of an organ
functionalWorking or operating
functional(of a mental illness) Having no discernible organic cause