Cavalry right to wear stockings (5)
I believe the answer is:
horse
'cavalry' is the definition.
(synonyms)
'right to wear stockings' is the wordplay.
'right' becomes 'r' (common abbreviation).
'to wear' means one lot of letters goes inside another (to wear something is to be covered up by it).
'stockings' becomes 'hose' (I've seen this in another clue).
'r' inserted within 'hose' is 'HORSE'.
(Other definitions for horse that I've seen before include "Equipment in gym" , "Shore (anag)" , "charger?" , "what has croup in the end?" , "Steed" .)