Horse bypasses solitary bull (7)
I believe the answer is:
baloney
'bull' is the definition.
(I've seen this in another clue)
'horse bypasses solitary' is the wordplay.
I cannot really see how this works, but
'solitary' could be 'lone' (synonyms) and 'lone' is located in the answer.
'horse' could be 'bay' (bay is a kind of horse) and 'bay' is present in the remaining letters.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for baloney that I've seen before include "foolish talk!" , "rhubarb" , "Nonsense; lean yob (anag)" , "Cobblers" , "Tosh" .)