Retiring party, almost packed (7)
I believe the answer is:
bashful
'retiring' is the definition.
(thesaurus)
'party almost packed' is the wordplay.
'party' becomes 'bash' (term for a party or celebration).
'almost' means to remove the last letter (almost the whole word is kept).
'packed' becomes 'full' (synonyms).
'full' with its last letter taken off is 'ful'.
'bash'+'ful'='BASHFUL'
(Other definitions for bashful that I've seen before include "One of Disney's dwarves" , "reserved" , "Shy, timid" , "Sleepy companion" , "Shy and self-conscious" .)