As nouns the difference between functional and groundskeeping
is that functional
is (mathematics) 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 while groundskeeping
is the activity of tending an area of land for aesthetic or functional purposes; typically as an employee of a person or institution.
As an adjective functional
is in good working order.