Answer: noticer

AnswerCrossword Clue
NOTICEROne who doesn't miss things
NOTICERObserver.
NOTICERWitness
NOTICERObservant type
noticerto mention
noticerinformation; warning
noticerto pay attention to or perceive
noticernote, sign, etc., that informs or warns
noticerattention; heed
noticerone who notices (to become aware of)