1) A Waifu Killer is someone who cosplays your favorite character preferable female anime character and you don't like the person for cosplaying the character you like.
2) Someone you dislikes who cosplays a favorite character of yours and you really don't want to see them as said character.
An umbrella term for a style of music (typically of the Future Bass and Chill genre) that contains many sounds from anime (such as gasps), particularly in accompaniment with anime thumbnails (especially female), and an overall 'vibe' that screams out, "I am a tremendous weeaboo".
Note; This does not stop the songs themselves from being at times decent.
Jimmy likes to listen to waifu music, all the anime sounds add one hair to his neckbeard for each over sexualised noise.