Japanese Slang! 軽い　かるい It usually means something or someone is Light (weight wise) But in a slangy way, it means someone’s behavior or determination is obviously fake! (Like no weight on the statement) Eg A: I will propose to my girlfriend today. B: Me too! Yaaaaay! A: 軽いな!w So whenever someone is not taking something seriously, you can say 軽いな！ Enjoy!