Hyperactive person in charge (5)
I believe the answer is:
manic
'hyperactive' is the definition.
'person in charge' is the wordplay.
'person' becomes 'man' (man is a kind of person**).
'in charge' becomes 'ic'.
'man'+'ic'='MANIC'
(Other definitions for manic that I've seen before include "Obsessive" , "Wildly energetic" , "Showing wild energy" , "Pathologically excited" , "Hectic" .)