Transplant a seedling (5)
I believe the answer is:
repot
'transplant a seedling' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for repot that I've seen before include "Transplant" , "place somewhere new to put down roots" , "Give room to expand" , "plant in another location" , "transfer seedlings" .)