Swimmer heading away from Beatrix? (5)
I believe the answer is:
otter
'swimmer' is the definition.
(animal which swims)
'heading away from beatrix?' is the wordplay.
'heading away from' means to remove the first letter.
'beatrix?' becomes 'Potter' (Beatrix Potter is an example).
'potter' with its first letter taken off is 'OTTER'.
(Other definitions for otter that I've seen before include "Riverine mammal" , "Holt dweller" , "furry animal" , "one that eats fish" , "Web-footed mammal" .)