Sounds of time passing (5)
I believe the answer is:
ticks
'sounds of time passing' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ticks that I've seen before include "Parasitic mites" , "Small arachnids" , "Signs of approval" , "Marks of approval" , "Parasitic arachnids" .)