Make mistakes penning answer, periodically applying this? (6)
I believe the answer is:
eraser
'this?' is the definition.
The definition suggests a singular noun which matches the answer.
'make mistakes penning answer periodically' is the wordplay.
'make mistakes' becomes 'err' (I've seen this before).
'penning' means one lot of letters goes inside another.
'periodically' means one should take alternating letters (letters must be selected 'every so often').
The alternating letters of 'answer' are 'ase'.
'err' placed around 'ase' is 'ERASER'.
'applying' is the link.
Can you help me to learn more?
(Other definitions for eraser that I've seen before include "A schoolboy's rubber" , "It's used to rub out" , "Rubbing-out device" , "(Pencil, ink) rubber" , "Item used for rubbing out" .)