Amiable but fishy offering made in sport! (6)
I believe the answer is:
gentle
'amiable' is the definition.
(I've seen this in another clue)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for gentle that I've seen before include "Jane Eyre's kind person with a book? -- eternal greed (anag)" , "Merciful -- grub" , "that may help angler catch fish" , "Not harsh or violent" , "Moderate in effect" .)