"Listen up!" (4)
(Other definitions for hey that I've seen before include "Call attracting attention" , "Exclamation calling attention" , "Exclamation to call attention" .)
(Other definitions for ahem that I've seen before include "Noise used to attract attention" , "Polite word to draw attention" , "Attention-getter" , "Sound used to attract attention" , "Utterance of mild disapproval" .)