Misleading action is weak, by the sound of it (5)
I believe the answer is:
Here is my best explanation:
'misleading action' is the definition.
'weak by the sound of it' is the subsidiary indication.
'weak' becomes 'faint' ('faint' can be similar in meaning to 'weak').
'by the sound of it' shows a homophone (sound like).
'faint' is a homophone of 'feint'.
'is' is the link.
(Other definitions for feint that I've seen before include "(Make a) deceptive move", "Pretended blow", "Misleading action", "Deceptive motion", "Artifice", "False fencing trust sounds dim", "Deceptive movement designed to distract", "Deceptive manoeuvre", "Sell a dummy" and "Mock attack".)