Opening hotel, displaying sluggishness (5)
I believe the answer is:
sloth
'sluggishness' is the definition.
(I've seen this before)
'opening hotel' is the wordplay.
'opening' becomes 'slot' (slot is a kind of opening).
'hotel' becomes 'h' (phonetic alphabet: alpha, bravo, charlie etc.).
'slot'+'h'='SLOTH'
'displaying' is the link.
(Other definitions for sloth that I've seen before include "Aversion to industry" , "Deadly sin - upside-down mammal" , "Arboreal animal" , "Laziness; slow mammal" , "Inertia" .)