Caught fifty others discarding royal garments (7)
I believe the answer is:
clothes
'garments' is the definition.
('clothe' can be a synonym of 'garment')
'caught fifty others discarding royal' is the wordplay.
'caught' becomes 'c' (cricket abbreviation).
'fifty' becomes 'l' (Roman numeral).
'discarding' suggests deleting specific letters.
'royal' becomes 'r' (abbreviation).
'others' with 'r' taken away is 'othes'.
'c'+'l'+'othes'='CLOTHES'
(Other definitions for clothes that I've seen before include "Items of apparel" , "Togs" , "Attire" , "Worn items" , "dresses" .)