Changed a little feeble content in series of talks (7)
I believe the answer is:
tweaked
'in series of talks' is the definition.
I can't judge whether this definition defines the answer.
'changed a little feeble content' is the wordplay.
'changed a little' becomes 'ted' (I can't explain this - if you can you should believe this answer much more).
'feeble' becomes 'weak' (similar in meaning).
'content' means one lot of letters goes inside another (some letters act as content for another word).
'ted' enclosing 'weak' is 'TWEAKED'.
Can you help me to learn more?
(Other definitions for tweaked that I've seen before include "Fine tuned" , "Slightly adjusted" , "altered" , "changed for the better" , "Pinched or twisted - or made fine adjustment" .)