functional
adjective
°In good working order.
°Useful; serving a purpose, fulfilling a function.
noun
°A function that takes a function as its argument; More precisely: A function y=f(x) whose argument x varies in a space of (real valued, complex valued) functions and whose value belongs to a monodimensional space. An example: the definite integration of integrable real functions in a real interval.
synonyms: functioning, working, utilitarian