Girl swimming Loch Fyne’s far end (5)
I believe the answer is:
chloe
'girl' is the definition.
(girl's name)
'swimming loch fyne's far end' is the wordplay.
'swimming' indicates anagramming the letters (letters swim around into a new order).
'far end' says to take the final letters (the letter at the far end of the word).
The last letter of 'fyne' is 'e'.
'loch' is an anagram of 'chlo'.
'chlo'+'e'='CHLOE'
(Other definitions for chloe that I've seen before include "She loved Daphnis" , "Girl's name" , "Daphnis et -, ballet by Ravel" , "Woman" , "young lady" .)