George, however, leaned in toward Hermione.
I've never seen the phrase "lean in toward" before. Is it a common collocation? What will be the difference between "leaned in toward Hermione" and "leaned toward Hermione"?
"Lean in" is itself a phrasal verb that acts much like "lean" by itself. "Lean in" is used to imply proximity or intimacy. "In" obviously refers to an inward direction, which enhances the sense of closeness between the subject and the object. The phrase can be used without "toward". For example:
He leaned in toward her to whisper, "Let's make a run for it. You distract the guards and I'll grab the keys."
He leaned to shout out the window, "You forgot your car keys!"
"Lean in" emphasizes a private moment, not meant to be overheard, while "lean" by itself only describes the position change. Another example:
She leaned in toward the painting in front of her to get a better look at the fine detail.
Here "in" emphasizes her desire to be close to the object of scrutiny, whereas "toward" on its own merely indicates the direction. For example, someone can lean toward a painting on the far side of a room, but it would not make sense to say that they leaned in toward a painting on the opposite side of a room, as the object would be too far away for the proximity implied by "lean in".
Inanimate objects can also "lean in":
The buildings on either side seemed to lean in toward the center of the narrow street, in an almost oppressive way. "Let's turn back," Ron suggested, clearly nervous.
The above example uses "lean in" to convey the enclosed feeling of being in a narrow street. Contrast this with the Leaning Tower of Pisa, which is only askew.