Equipment packed in luggage arrives (4)
I believe the answer is:
gear
'equipment' is the definition.
(gear is a kind of equipment)
'packed in luggage arrives' is the wordplay.
'packed in' says the answer is hidden in the clue.
'GEAR' is hidden within 'luggage arrives'.
(Other definitions for gear that I've seen before include "Toothed wheel used when changing speed" , "often changed when driving" , "Clothing - tackle" , "Clothes -- paraphernalia" , "Clothes - equipment - first to fifth in a car?" .)