Now history lecturer's beginning to get close, making improper advances? (11)

'making improper advances?' is the definition.
I can't tell whether this definition defines the answer.

'now history lecturer's beginning to get close' is the wordplay.
I cannot quite understand how this works, but
'history' could be 'over' (I've seen this in another clue) and 'over' is present in the answer.
'close' could be 'ending' (synonyms) and 'ending' is present in the answer.
'lecturer' could be 'l' (abbreviation for lecturer) and 'l' is found within the answer.
No letters remain.
This explanation may well be incorrect...

Can you help me to learn more?