The Asian jockey with abnormal physical weakness (8)
I believe the answer is:
asthenia
'abnormal physical weakness' is the definition.
'asthenia' can be an answer for 'weakness' (I've seen this before). I'm not sure about the 'abnormal physical' bit.
'the asian jockey' is the wordplay.
'jockey' indicates an anagram (the letters scramble or jockey around).
'the'+'asian'='theasian'
'theasian' with letters rearranged gives 'ASTHENIA'.
'with' is the link.
Can you help me to learn more?
(Other definitions for asthenia that I've seen before include "Weakness" , "loss of strength" .)