Figure to start talks - that's essential (5)
I believe the answer is:
vital
'essential' is the definition.
(similar in meaning)
'figure to start talks' is the wordplay.
'figure' becomes 'l' (I've seen this in other clues).
'to' is a charade indicator (letters next to each other) (I've seen this in other clues).
'start talks' becomes 'vita' (I can't explain this - if you can you should give a lot more credence to this answer).
'l' after 'vita' is 'VITAL'.
'that's' acts as a link.
Can you help me to learn more?
(Other definitions for vital that I've seen before include "Of key importance" , "Characteristic of life" , "Imperative" , "Essential to life, indispensable" , "Essential to life or critically important" .)