Animal that's quiet around crowd (5)
I believe the answer is:
sloth
'animal' is the definition.
(sloth is a kind of animal)
'quiet around crowd' is the wordplay.
'quiet' becomes 'sh'.
'around' indicates putting letters inside.
'crowd' becomes 'lot' (I've seen this in other clues).
'sh' going around 'lot' is 'SLOTH'.
'that's' is the link.
(Other definitions for sloth that I've seen before include "Indolence" , "Lethargy" , "Laziness; slow mammal" , "Inertia" , "One hangs a lot" .)