Lecturer entertaining one is more willing (7)
I believe the answer is:
readier
'more willing' is the definition.
('ready' can be similar in meaning to 'willing')
'lecturer entertaining one' is the wordplay.
'lecturer' becomes 'reader' (synonyms).
'entertaining' is an insertion indicator (inviting in, as for dinner).
'one' becomes 'i' (Roman numeral).
'reader' placed around '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" .)