Become more active in social, taking girl away from jerk (3,2)
I believe the answer is:
hot up
'become' is the definition.
The definition and answer can be both related to change as well as being verbs in their base form.
Perhaps they are linked in a way I don't understand?
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for hot up that I've seen before include "more active" , "become more lively" , "Become more exciting" , "intensify" .)