Giant boob at Wembley, possibly concerning (4)
I believe the answer is:
ogre
'giant' is the definition.
(ogre is a kind of giant)
'boob at wembley possibly concerning' is the wordplay.
I cannot quite see how this works, but
'concerning' could be 're' (both can mean on a particular topic) and 're' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for ogre that I've seen before include "Fairy-tale creature" , "Fairy tale monster" , "Fierce giant" , "Terrifying monster" , "Bugbear" .)