It's clever to move fast (3)
I believe the answer is:
fly
This clue might be a double definition.
'it's clever' is the first definition.
'move fast' is the second definition.
'fly' can be an answer for 'move' (flying is a kind of moving). I am not sure about the 'fast' bit.
'to' acts as a link.
Can you help me to learn more?
(Other definitions for fly that I've seen before include "SECOND PART OF 14" , "Take wing" , "One invited into parlour" , "Insect; rush" , "Travel through the air" .)