Perhaps tip-off impacted new charges (4)
I believe the answer is:
hint
'perhaps tip' is the definition.
'hint' can be an answer for 'tip' (I've seen this in another clue). I am not certain of the 'perhaps' bit.
'impacted new charges' is the wordplay.
'impacted' becomes 'hit' (hit can mean to impact or crash into).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'charges' means one lot of letters goes inside another (charge can mean to charge into something).
'hit' enclosing 'n' is 'HINT'.
'off' acts as a link.
Can you help me to learn more?
(Other definitions for hint that I've seen before include "Helpful suggestion" , "A dash" , "Piece of advice" , "suspicion" , "Tip, clue" .)