Chap in charge is frenzied (5)
I believe the answer is:
manic
'frenzied' is the definition.
(I know that frenzied can be written as manic)
'chap in charge' is the wordplay.
'chap' becomes 'man' (chap can mean a man).
'in charge' becomes 'ic' (abbreviation for 'in charge').
'man'+'ic'='MANIC'
'is' acts as a link.
(Other definitions for manic that I've seen before include "demented" , "Berserk" , "hyperactive?" , "Frenetic, mad" , "Hectic" .)