Assassin's heavy footwear's hard at the tip (5)
I believe the answer is:
booth
'assassin's' is the definition.
(John Wilkes Booth shot Abraham Lincoln)
'heavy footwear's hard at the tip' is the wordplay.
'heavy footwear' becomes 'boo' (I can't justify this - if you can you should give a lot more credence to this answer).
'hard' becomes 'h' (abbreviation used in pencil classifications).
'at' means one lot of letters go next to another (I've seen this in other clues).
'tip' says to take the initial letters (one tip of the word).
The initial letter of 'the' is 't'.
'h' after 't' is 'th'.
'boo'+'th'='BOOTH'
Can you help me to learn more?
(Other definitions for booth that I've seen before include "Stall - Salvation Army founder" , "Killer of president" , "compartment for voting" , "Market stall - Lincoln's assassin" , "Cubicle - Salvation Army founder" .)