The Speaker’s flummoxed, displaying weakness (6)
I believe the answer is:
flawed
'displaying weakness' is the definition.
(having a flaw or weakness)
'the speaker's flummoxed' is the wordplay.
'the speaker's' shows a homophone (sound like) (as it might sound when spoken).
'flummoxed' becomes 'floored' (both can mean shocked or puzzled).
'floored' is a homophone of 'FLAWED'.
(Other definitions for flawed that I've seen before include "wrong" , "Having blemish or defect" , "Imperfect" , "Containing blemish or imperfection" , "Blemished; faulty" .)