Personal support by nameless friend is genuine (10)
I believe the answer is:
legitimate
'genuine' is the definition.
(I've seen this before)
'personal support by nameless friend' is the wordplay.
I cannot really understand how this works, but
'support' could be 'leg' (leg is a kind of support) and 'leg' is located in the answer.
'by' could be 'at' and 'at' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
'is' is the link.
Can you help me to learn more?
(Other definitions for legitimate that I've seen before include "fair" , "Permitted" , "In accordance with the rules" , "It's admissible" , "Kosher" .)