clever: showing inventiveness and skill; "a clever gadget"; "the cunning maneuvers leading to his success"; "an ingenious solution to the problem"
(ingeniously) in an ingenious manner; "a Hampshire farmer had fowls of different breeds, including Dorkings, and he discriminated ingeniously between the `dark ones' and the `white ones'"
(ingeniousness) ingenuity: the property of being ingenious; "a plot of great ingenuity"; "the cleverness of its design"
Ingenious is a one-off drama produced by Lime Pictures written especially for CBBC. It premiered on BBC One.
A development or an improvement is considered ingenious if it is not obvious to workers of average skill in this area of technology.
X's proof is ingenious: I understand it.