Shout down my left ear at first (6)
I believe the answer is:
heckle
'shout down' is the definition.
(I've seen this before)
'my left ear at first' is the wordplay.
'my' becomes 'heck' (I am not sure about this - if you are sure you should believe this answer much more).
'at first' indicates taking the first letters.
The initial letters of 'left ear' is 'le'.
'heck'+'le'='HECKLE'
Can you help me to learn more?
(Other definitions for heckle that I've seen before include "Interrupt (speaker) with abuse" , "Jeer or interrupt speaker from crowd" , "Barrack speaker" , "Shout down (a politician)" , "Shout disruptively at performer" .)