One backed by Leonid to even run spy (8)
I believe the answer is:
endorsee
'one backed' is the definition.
I can't tell whether this defines the answer.
'leonid to even run spy' is the wordplay.
'even' means one should take alternating letters (even-numbered letters are used).
'run' becomes 'r' (cricket abbreviation).
'spy' becomes 'see' (spy can mean to watch or see).
'leonid'+'to'='leonidto'
The alternate letters of 'leonidto' are 'endo'.
'endo'+'r'+'see'='ENDORSEE'
'by' acts as a link.
Can you help me to learn more?
(Other definitions for endorsee that I've seen before include "he eventually gets cheque" , "one given money?" , "One to whom cheque is assigned" .)