Pack up an ear-piece in a box (5)
I believe the answer is:
cease
'pack up' is the definition.
'cease' can be an answer for 'pack' (thesaurus). I'm not certain of the 'up' bit.
'an ear-piece in a box' is the wordplay.
'an ear-piece' becomes 'e' (this could be a standard abbreviation of which I'm unaware).
'in' means one lot of letters goes inside another.
'a box' becomes 'case' (I've seen this before).
'e' inserted into 'case' is 'CEASE'.
Can you help me to learn more?
(Other definitions for cease that I've seen before include "Political group" , "Come to an end" , "Discontinue" , "Stop, finish" , "Desist" .)