Twisted healthy wolf's tail in squabble (4)
I believe the answer is:
tiff
'squabble' is the definition.
('tiff' can be a synonym of 'squabble')
'twisted healthy wolf's tail' is the wordplay.
'twisted' says the letters should be written in reverse.
'healthy' becomes 'fit' ('fit' is associated in meaning with 'healthy').
'tail' suggests the final letters.
The last letter of 'wolf' is 'f'.
'fit' written backwards gives 'tif'.
'tif'+'f'='TIFF'
'in' is the link.
(Other definitions for tiff that I've seen before include "dispute" , "Petty squabble" , "Petty argument" , "A minor quarrel of disagreement" , "Slight quarrel" .)