Loyal Tories beat rest finally (8)
I believe the answer is:
constant
'loyal' is the definition.
(thesaurus)
'tories beat rest finally' is the wordplay.
'tories' becomes 'cons' (I've seen this in other clues).
'beat' becomes 'tan' (I've seen this before).
'finally' says to take the final letters.
The final letter of 'rest' is 't'.
'cons'+'tan'+'t'='CONSTANT'
(Other definitions for constant that I've seen before include "Stable" , "Continuous" , "exactly as before" , "Unwavering" , "Always - faithful" .)