Leader of people inclined to be flexible (7)
I believe the answer is:
pliable
'flexible' is the definition.
('pliable' can be similar in meaning to 'flexible')
'leader of people inclined' is the wordplay.
'leader of' suggests taking the first letters.
'inclined' becomes 'liable' (I've seen this before).
The initial letter of 'people' is 'p'.
'p'+'liable'='PLIABLE'
'to be' is the link.
(Other definitions for pliable that I've seen before include "Elastic" , "Easily bent" , "accommodating" , "Flexible" , "easily influenced" .)