Solution: A Mud-Soled Lubber

SOLUTION:

This list of words can be broken up into 16 Harry Potter quotes, each with a word missing. The actual quotes (with missing word capitalized):

Quote	book/page/chapter
He raised his own wand, ATTEMPTED a complicated sort of wiggling action, and dropped it.	#2, Dueling Club
Was the Grim going TO haunt him until he actually died?	#3
because the smiling lady in the van had asked HARRY what he wanted before they could hurry him away they bought him a cheap lemon ice pop	#1, p26
I bet he'd've pitched him off the bike HALFWAY out ter sea.	#3, p154
He bent DOWN, picked up the door, and fitted it easily back into its frame.	#1, p47
Robes, jade-green, lilac, midnight blue, had been hastily folded into one of them; books were jumbled untidily into THE other.	#2, p296
half laughing half crying running to keep up with the TRAIN until it gathered too much speed then she fell back and waved	#1, p98
And then a horribly familiar wave of cold swept over him, inside him, just AS he became aware of something moving on the pitch below.	#3
As HE pulled on his scarlet robes in the locker room, his only comfort was that everyone was not outside to watch the game.	#2
A pale young man MADE his way forward very nervously.	#1, p70
He tapped the wall three times with the point of HIS umbrella.	#1, p71
He slid a considerable WAY down what felt like a stone slide, then landed on cold, damp earth.	#3, Marauder's Map
He had been staring absentmindedly into the hedge, and the hedge was staring BACK.	#2, p8
He pines if he's away FROM me.	#3, p23
fear of a name increases fear of THE thing itself	#1, p298
Three glass tumblers stood ready on the TOILET seat.	#2

When you take the missing words, they are the last part of this quote:

Firstly, Malfoy, Crabbe, and Goyle, who had clearly been waiting all week for the opportunity to strike without teacher witnesses, attempted to ambush Harry halfway down the train as he made his way back from the toilet.(#5, p. 864)

The word AMBUSH is missing.