Pack up and post, perhaps (4)
I believe the answer is:
stop
'pack up' is the definition.
'stop' can be an answer for 'pack' (thesaurus). I'm not sure about the 'up' bit.
'post perhaps' is the wordplay.
'perhaps' is an anagram indicator.
'post' anagrammed gives 'STOP'.
'and' acts as a link.
Can you help me to learn more?
(Other definitions for stop that I've seen before include "Come to a halt" , "Organ knob; get bus here" , "Withhold payment" , "colon, say" , "This watch is used to time races" .)