Shoot to start some underground movement (9)
I believe the answer is:
germinate
'shoot' is the definition.
(I know that shoot can be written as germinate)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for germinate that I've seen before include "(Of seed) start to shoot" , "come to life" , "(Of seeds) sprout" , "Spring up" , "Sprout as in a regiment" .)