Article on gallery after negative comment (8)
I believe the answer is:
annotate
'comment' is the definition.
(thesaurus)
'article on gallery after negative' is the wordplay.
'article' becomes 'an' (indefinite article).
'on' says to put letters next to each other.
'gallery' becomes 'tate' (I've seen this before).
'after' means one lot of letters go next to another.
'negative' becomes 'no' (no is a kind of negative).
'tate' put after 'no' is 'notate'.
'an' next to 'notate' is 'ANNOTATE'.
(Other definitions for annotate that I've seen before include "Make notes upon" , "Add explanatory comments" , "Write down comments on" , "Supply explanatory notes" , "Add explanations and comments to (a text)" .)