Easier wiping lecturer's silly smile (6)
I believe the answer is:
simper
'silly smile' is the definition.
(I've seen this in another clue)
'easier wiping lecturer's' is the wordplay.
'easier' becomes 'simpler' (I've seen this before).
'wiping' indicates named letters should be taken away.
'lecturer' becomes 'l' (abbreviation for lecturer).
'simpler' with 'l' removed is 'SIMPER'.
(Other definitions for simper that I've seen before include "Smile ingratiatingly" , "Silly self-conscious smile" , "affect a smile" , "Primes to smile in affected way" , "Snigger" .)