Discuss revolutionary plot over high tea (6)
I believe the answer is:
debate
'discuss' is the definition.
(debating is a kind of discussing)
'revolutionary plot over high tea' is the wordplay.
'revolutionary' is a reversal indicator (letters revolve around).
'plot' becomes 'bed' (a plot of land).
'over' means one lot of letters go next to another (in a down clue, some letters go over others).
'high' indicates an anagram (like drunk).
'bed' written backwards gives 'deb'.
'tea' is an anagram of 'ate'.
'deb'+'ate'='DEBATE'
(Other definitions for debate that I've seen before include "Verbal disputation" , "Heated discussion" , "Talk" , "Discussion throung argument" , "Discuss; argue" .)