Closing plant? Case of farewell, have fun in retirement (7)
I believe the answer is:
flytrap
'closing plant?' is the definition.
'flytrap' can be an answer for 'plant?'. I'm not certain of the 'closing' bit.
'case of farewell have fun in retirement' is the wordplay.
'case of' means to remove the middle letters (outsides of).
'have fun in' becomes 'party' (I can't justify this - if you can you should believe this answer much more).
'retirement' is a reversal indicator (retire can mean to return or go back).
'farewell' with its centre taken out is 'fl'.
'party' back-to-front is 'ytrap'.
'fl'+'ytrap'='FLYTRAP'
Can you help me to learn more?
(Other definitions for flytrap that I've seen before include "Venus ...., carnivorous plant" , "Specialised plant" , "that'll take six-footers" .)