functional, usable, useable, in working order, operable, operational - 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" Antonym:unserviceable (indirect, via serviceable)
operational, in operation, operating - being in effect or operation; "de facto apartheid is still operational even in the `new' African nations"- Leslie Marmon Silko; "bus service is in operation during the emergency"; "the company had several operating divisions" Antonym:inoperative (indirect, via operative)