Stir things up at a number of points (5)
I believe the answer is:
liven
'stir things up' is the definition.
I can't judge whether this definition defines the answer.
'at a number of points' is the wordplay.
'at' says to put letters next to each other.
'a number' becomes 'n' (n can represent any number).
'of points' becomes 'live' (I am not sure about this - if you are sure you should believe this answer much more).
'n' after 'live' is 'LIVEN'.
Can you help me to learn more?
(Other definitions for liven that I've seen before include "Invigorate" , "Make active" , "Cause excitement" , "Animate, make energetic" , "Make (something) more interesting" .)