Reptiles like empty places (4)
I believe the answer is:
asps
'reptiles' is the definition.
(asp is a kind of reptile)
'like empty places' is the wordplay.
'like' becomes 'as'.
'empty' says to hollow out the word (remove centre letters).
'places' with its middle taken out is 'ps'.
'as'+'ps'='ASPS'
(Other definitions for asps that I've seen before include "Poplars" , "Pass around the snakes" , "Pass among snakes" , "native Africans?" , "poisonous things" .)