Here are some words I really like.
Sostenuto. Largo. Adagio. C Sharp Minor. Dolce. Affannoso.
Dolente. Lento. Lacrimoso. Langsam. Mancando. Immortal.
Beloved.
My advice when listening to this movement.
Close your eyes and think of the scene in "Immortal Beloved", when
Gary Oldman is "auditioning" and he places his head on the piano
in order to "feel" the music. If you are lucky enough to know someone
who can play this piece well, try this yourself, while they play.
Ideally, it works best if you can stick your head in the top of a Grand Piano.
Wilhelm Kempff plays Beethoven's Moonlight Sonata mvt. 1
Daniel Barenboim - Moonlight sonata - 1ºmov Adagio sostenuto