Look pleased — Robert’s opening spirit bottles (4)
I believe the answer is:
grin
'look pleased' is the definition.
(I've seen this before)
'robert's opening spirit bottles' is the wordplay.
'opening' indicates taking the first letters.
'spirit' becomes 'gin' (alcoholic spirit).
'bottles' means one lot of letters goes inside another (bottle can mean to contain).
The first letter of 'robert' is 'r'.
'r' placed inside 'gin' is 'GRIN'.
(Other definitions for grin that I've seen before include "Smirk" , "Smile wryly" , "Facial expression showing amusement or pleasure" , "Beam" , "show ivories happily with it" .)