ˈfʌŋk(t)ʃənəl ˈɒ.pə.ɹə.bəl ˈɒpəɹətɪv ˈɹʌnɪŋ ˈjuː.zə.bəl designed for or capable of a particular function or use a style of writing in which every word is functional functional architecture (of e.g. a machine) performing or capable of performing in running (or working) order a functional set of brakes involving or affecting function rather than physiology functional deafness 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 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 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