Opening hours for animal (5)
I believe the answer is:
sloth
'for animal' is the definition.
(sloth is a kind of animal)
'opening hours' is the wordplay.
'opening' becomes 'slot' (slot is a kind of opening).
'hours' becomes 'h'.
'slot'+'h'='SLOTH'
(Other definitions for sloth that I've seen before include "Deadly sin - upside-down mammal" , "Slow-moving arboreal mammal" , "Indolence" , "Arboreal creature" , "Torpor" .)