Hack, for one, runs in tights (5)
I believe the answer is:
horse
'hack for one' is the definition.
(hack is a kind of horse)
'runs in tights' is the wordplay.
'runs' becomes 'r' (cricket abbreviation).
'in' indicates putting letters inside.
'tights' becomes 'hose' (synonyms).
'r' inserted inside 'hose' is 'HORSE'.
(Other definitions for horse that I've seen before include "It may get people stoned" , "Equine animal" , "farm animal" , "Vaulting apparatus" , "Quadruped; cavalry" .)