Run in a lawful way (3,2)
I believe the answer is:
leg it
'run in a lawful way' is the definition.
The answer and definition can be both to do with motion as well as being verbs in their base form.
Maybe there's an association between them I don't understand?
This is all the clue.
Can you help me to learn more?
(Other definitions for leg it that I've seen before include "Escape" , "Run away" .)