Hurry up and put your foot down (4,2,2)
I believe the answer is:
step on it
'hurry up' is the definition.
(I've seen this before)
'put your foot down' is the wordplay.
I cannot really see how this works, but
'put your foot down' could be 'step' (I've seen this in another clue) and 'step' is located in the answer.
The remaining letters 'onit' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'and' acts as a link.
Can you help me to learn more?
(Other definitions for step on it that I've seen before include "Go faster - put foot down" , "Hurry! - set point (anag)" , "Get a move on!" , "Go for speed" , "How might one kill an ant" .)