Hole, see, inside cube (4)
I believe the answer is:
dive
'hole' is the definition.
(thesaurus)
'see inside cube' is the wordplay.
'see' becomes 'v' (Latin 'vide', used to direct a reader to a source).
'inside' indicates putting letters inside.
'cube' becomes 'die' (die is a kind of cube).
'v' inserted into 'die' is 'DIVE'.
(Other definitions for dive that I've seen before include "Swim under water" , "Plunge head first" , "Jump into water" , "Seedy bar" , "Disreputable establishment" .)