Answer: kibitzer

AnswerCrossword Clue
KIBITZERPest of a sort
KIBITZERFifth wheel at the card table.
KIBITZERPoker pest
kibitzera giver of uninvited or unwanted advice.
kibitzerone who kibitzes (to give unwelcome advice, also KIBBITZ)
kibitzerperson offering unwanted advice