Lecturer entertaining one is more willing (7)
I believe the answer is:
readier
'more willing' is the definition.
('ready' is associated in meaning with 'willing')
'lecturer entertaining one' is the wordplay.
'lecturer' becomes 'reader' (synonyms).
'entertaining' indicates putting letters inside (inviting in, as for dinner).
'one' becomes 'i' (Roman numeral).
'reader' enclosing 'i' is 'READIER'.
'is' acts as a link.
(Other definitions for readier that I've seen before include "more immediately available" , "More prepared" , "More willing" .)