Star with negative velocity and acceleration (4)
I believe the answer is:
nova
'star' is the definition.
(nova is a kind of star)
'negative velocity and acceleration' is the wordplay.
'negative' becomes 'no' (no is a kind of negative).
'velocity' becomes 'v'.
'and' is a charade indicator (letters next to each other).
'acceleration' becomes 'a' (symbol used in Physics e.g. f=ma).
'no'+'v'+'a'='NOVA'
'with' acts as a link.
(Other definitions for nova that I've seen before include "Sudden light increase" , "Suddenly expanding star" , "Star showing a sudden temporary increase in brightness" , "Kind of star" , "Star that becomes much brighter for short time" .)