Pearl's upset about Charlie getting a package (6)
I believe the answer is:
parcel
'a package' is the definition.
('parcel' can be a synonym of 'package')
'pearl's upset about charlie' is the wordplay.
'upset' indicates anagramming the letters.
'about' means one lot of letters goes inside another.
'charlie' becomes 'c' (phonetic alphabet: alpha, bravo, charlie etc.).
'pearl' anagrammed gives 'parel'.
'parel' going around 'c' is 'PARCEL'.
'getting' is the link.
(Other definitions for parcel that I've seen before include "Wrapped missive" , "Package; piece of land" , "Small piece of land" , "plot" , "One wrapped" .)