Carve the rocks around cave's entrance (4)
I believe the answer is:
etch
'carve' is the definition.
(to etch is to carve into a material)
'the rocks around cave's entrance' is the wordplay.
'rocks' indicates an anagram.
'around' indicates putting letters inside.
'entrance' indicates taking the first letters.
The first letter of 'caves' is 'c'.
'the' anagrammed gives 'eth'.
'eth' placed around 'c' is 'ETCH'.
(Other definitions for etch that I've seen before include "Carve or engrave into surface" , "Incribe" , "Prepare artwork" , "Engrave (glass/metal)" , "Engrave; fix firmly" .)