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' is an insertion indicator.
'charlie' becomes 'C' (phonetic alphabet).
'pearl' anagrammed gives 'parel'.
'parel' going around 'c' is 'PARCEL'.
'getting' acts as a link.
(Other definitions for parcel that I've seen before include "Wrapped missive" , "Package; piece of land" , "Small piece of land" , "plot" , "One wrapped" .)