Big dipper (5)
'big dipper' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for roller coaster that I've seen before include "Fairground ride" , "Series of emotional swings" , "scenic railway" , "Big dipper" , "entertainment at fair" .)
(Other definitions for ladle that I've seen before include "Soup-server" , "give out" , "Large deep spoon for serving soup" , "Scoop" , "Large spoon with long handle" .)