of or pertaining to a function or functions

functional difficulties in the administration.

capable of operating or functioning

When will the ventilating system be functional again?

having or serving a utilitarian purpose; capable of serving the purpose for which it was designed

functional architecture; a chair that is functional as well as decorative.

Also, functionalistic. (of a building or furnishing) constructed or made according to the principles of functionalism or primarily as a direct fulfillment of a material need.

Medicine/Medical . without a known organic cause or structural change

a functional disorder. Compare organic def. 5

pertaining to an algebraic operation

a functional symbol.

Linguistics . (of linguistic analysis, language teaching, etc.) concerned with the communicative role of language rather than, in addition to, or as the framework for its formal structure.

Mathematics . a function that has a domain whose elements are functions, sets, or the like, and that assumes numerical values.

adjective

broken , idle , malfunctioning , unfunctional

adjective

handy , occupational , operative , practicable , practical , serviceable , useful , utile , utilitarian , utility , working