Answer: observer

AnswerCrossword Clue
OBSERVERLondon weekly, with "The"
OBSERVEREyewitness
OBSERVEROnlooker
observerA person who attends a conference, inquiry, etc., to note the proceedings without participating in them
observerA person who watches or notices something
observerone that observes (to view (to look at))
observerA person who follows events, esp. political ones, closely and comments publicly on them
observer(in science or art) A real or hypothetical person whose observation is regarded as having a particular viewpoint or effect
observerA person posted to an area in an official capacity to monitor political or military events