Based on the function input-output pairs provided, here is a description of the function implemented by f(x):

[DESCRIPTION]: The function f(x) appears to be selective for the concept of "Tour de France". When words related to the Tour de France, such as "helmet" and "Eiffel Tower" are passed as inputs to the function, it returns a value very close to 1 (0.9962 and 0.6188, respectively). On the other hand, when unrelated words like "geometry", "hypothesis", "Cold War", "old", "organs", "highway", and "earthquake" are passed as inputs, the function returns values closer to 0 (ranging from 0.0002 to 0.0090).

It is important to note, however, that the function does not solely depend on the concept of "Tour de France". There might be some association with other concepts as well based on the output values for other inputs. Further exploration and testing with a variety of words would be needed to accurately determine all the concepts for which f(x) is selective.

Please let me know if there is anything else I can assist you with.