It initiates the question of a pointed hat (4)
I believe the answer is:
what
'question of a pointed hat' is the definition.
'what' can be an answer for 'question' (what is a question word). I am unsure of the 'of a pointed hat' bit.
'it initiates the' is the wordplay.
'it' becomes 'wha' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'initiates' indicates taking the first letters (I've seen 'initiated' mean this).
The first letter of 'the' is 't'.
'wha'+'t'='WHAT'
Can you help me to learn more?
(Other definitions for what that I've seen before include "That which - come again!" , "I beg your pardon" , "Interrogatory word" , "Word used in a question" , "Which thing?" .)