Something thrown from carriages safely picked up (7)
I believe the answer is:
assegai
'something thrown' is the definition.
(spear)
'from carriages safely picked up' is the wordplay.
'from' indicates the answer is hidden within the clue.
'picked up' says the letters should be written in reverse.
'iagessa' can be found hidden inside 'carriages safely'.
'iagessa' back-to-front is 'ASSEGAI'.
(Other definitions for assegai that I've seen before include "spear made from wood" , "Ages as I threw the spear" , "A Zulu war spear" , "something pointed" , "Spear used in southern Africa" .)