Mean guitarist's last set (5)
I believe the answer is:
plant
'set' is the definition.
(planting is a kind of setting)
'mean guitarist's last' is the wordplay.
'mean' becomes 'plan' (planning is a kind of meaning).
'last' suggests the final letters.
The last letter of 'guitarist' is 't'.
'plan'+'t'='PLANT'
(Other definitions for plant that I've seen before include "Shrub - factory" , "Put in soil" , "Hide in order to be found" , "One placed in a group as an informer" , "Factory; informer" .)