Someone standing outside the Great Hall might well have thought some
sort of explosion had taken place, so loud was the noise that erupted
from the Gryffindor table. Harry, Ron, and Hermione stood up to yell
and cheer as Neville, white with shock, disappeared under a pile of
people hugging him. He had never won so much as a point for Gryffindor
before. Harry, still cheering, nudged Ron in the ribs and pointed at
Malfoy, who couldn’t have looked more stunned and horrified if
he’d just had the Body-Bind Curse put on him.
(Harry Potter and the Sorcerer’s Stone)
If seems to have a meaning of ‘even though’, but OALD and Merriam-Webster’s only have cases used before adjectives to introduce contrasts. Can ‘if’ have the meaning of ‘even though’ before a clause, too?
If is used to introduce a contingency, something which might happen; here it introduces a counterfactual contingency, an event which has not happened. Malfoy was not cursed, but even if he had been cursed he could not have looked any more stunned.
Though or although is only used to introduce actualities, things which have happened. Even though he had just had … would imply that Malfoy DID have the curse put on him, which is not the case here.
Source : Link , Question Author : Listenever , Answer Author : StoneyB on hiatus