Vowelless Scrabble play (3)
(Other definitions for nth that I've seen before include "Umpteenth" , "To the -- degree" .)
(Other definitions for psst that I've seen before include "Sibilant sound to attract attention furtively" , "Sound used to attract someone's attention" , "attempt to attract attention" , "Soft sound to get someone's attention" , "Quiet call for attention" .)