Stop one working for stud (8)
I believe the answer is:
stallion
'stud' is the definition.
(thesaurus)
'stop one working' is the wordplay.
'stop' becomes 'stall' (stalling is a kind of stopping**).
'one' becomes 'i' (Roman numeral).
'working' becomes 'on'.
'stall'+'i'+'on'='STALLION'
'for' is the link.
(Other definitions for stallion that I've seen before include "Male horse lost in atolls" , "Uncastrated adult male horse" , "Male steed" , "Male horse, often used for breeding" , "Mount" .)