Quick learner, free from affectation (7)
I believe the answer is:
natural
I believe this is a double definition.
'quick learner' is the first definition.
(someone who is a natural at something)
'free from affectation' is the second definition.
(that which is not affected)
(Other definitions for natural that I've seen before include "Unaffected, normal in manner" , "(Of fabric) off-white" , "Innate, inborn" , "Relaxed, unaffected" , "person regarded as certain to qualify" .)