Maniac putting a jerk on air (7)
I believe the answer is:
fanatic
'maniac' is the definition.
(thesaurus)
'a jerk on air' is the wordplay.
'jerk' becomes 'tic' (jerking movement by the body).
'on' means one lot of letters go next to another.
'air' becomes 'fan' (I am not sure about this - if you are sure you should believe this answer much more).
'a'+'tic'='atic'
'atic' after 'fan' is 'FANATIC'.
'putting' acts as a link.
Can you help me to learn more?
(Other definitions for fanatic that I've seen before include "Zealot or extremist" , "crank" , "Person filled with excessive zeal for cause" , "Freak" , "enthusiastic" .)