Don't just look (3)
I believe the answer is:
are
'don't just look' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for are that I've seen before include "(We/they/you) exist" , "Exist; square measure" , "(They/you/we) exist" , "Era (anag.)" , "Unit of land measure equal to 100 square metres" .)