Remember watch, say (7)
I believe the answer is:
observe
This clue is a triple definition!
'remember' is the first definition.
(thesaurus)
'watch' is the second definition.
(observing is a kind of watching)
'say' is the third definition.
(I know this)
(Other definitions for observe that I've seen before include "Notice; study" , "Watch without intervening" , "Abide by -- watch" , "Watch attentively" , "Verbose (anag.)" .)