Large group (5)
'large group' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for horde that I've seen before include "Migratory tribe; army" , "Many people" , "lots of people" , "A moving crowd" , "Great crowd" .)
'large group' is the definition.
(large group of animals or people)
This is the entire clue.
(Other definitions for bevy that I've seen before include "Gaggle" , "hen party" , "Group (of larks, ladies etc)" , "Group, of beauties perhaps (4)" , "Flock of larks; group of beautiful women" .)