Cool online talks with very good content (5)
I believe the answer is:
tepid
'cool' is the definition.
(thesaurus)
'online talks with very good content' is the wordplay.
'online talks' becomes 'ted' (TED Talks).
'with' is an insertion indicator.
'very good content' becomes 'pi' (I am not sure about this - if you are sure you should believe this answer much more).
'ted' placed around 'pi' is 'TEPID'.
Can you help me to learn more?
(Other definitions for tepid that I've seen before include "without passion" , "Unenthusiastic - cool" , "lacking enthusiasm" , "Showing little interest or enthusiasm" , "Luke warm" .)