Watch, say (7)
I believe the answer is:
observe
I believe this clue is a double definition.
'watch' is the first definition.
(I know that watch can be written as observe)
'say' is the second definition.
(observing is a kind of saying)
(Other definitions for observe that I've seen before include "Espy" , "Notice or conform to, rules say" , "See - say" , "Notice, watch" , "Abide by -- watch" .)