First-class supple athletic type (7)
I believe the answer is:
climber
'athletic type' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe there's a link between them I don't understand?
'first-class supple' is the wordplay.
'first class' becomes 'c' (1st letter of 'class').
'supple' becomes 'limber' (synonyms).
'c'+'limber'='CLIMBER'
Can you help me to learn more?
(Other definitions for climber that I've seen before include "Plant such as ivy" , "Edward Whymper, for example" , "Plant that grows up a support" , "in the garden" , "Bonnington" .)